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  • Data base design with Blob

    - by mmuthu
    Hi, I have a situation where i need to store the binary data into database as blob column. There are three different table exists in my database where in i need to store a blob data for each record. Not every record will have the blob data all the time. It is time and user based. The table one will have to store the *.doc files almost for all the record The table two will have to store the *.xml optionally. The table three will have to store images (not sure what is frequency, etc) Now my questions is whether it is a good idea to maintain a separate table to store the blob data pointing it to the respective table PK's (Yes, there will be no FK's and assuming program will maintain it). It will be some thing like below, BLOB|PK_ID|TABLE_NAME Alternatively, is it a good idea to keep the blob column in respective tables. As for as my application runtime is concerned, The table 2 will be read very frequently. Though the blob column will not be required. The table 2 record will gets deleted frequently. Similarly other blob data in respective table will not be accessed frequently. All of the blob content will be read on-demand basis. I'm thinking first approach will work better for me. What do you guys think? Btw, I'm using Oracle.

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  • How to increase my "advanced" knowledge of PHP further? (quickly)

    - by Kerry
    I have been working with PHP for years and gotten a very good grasp of the language, created many advanced and not-so-advanced systems that are working very well. The problem I'm running into is that I only learn when I find a need for something that I haven't learned before. This causes me to look up solutions and other code that handles the problem, and so I will learn about a new function or structure that I hadn't seen before. It is in this way that I have learned many of my better techniques (such as studying classes put out by Amazon, Google or other major companies). The main problem with this is the concept of not being able to learn something if you don't know it exists. For instance, it took me several months of programming to learn about the empty() function, and I simply would check the string length using strlen() to check for empty values. I'm now getting into building bigger and bigger systems, and I've started to read blogs like highscalability.com and been researching MySQL replication and server data for scaling. I know that structure of your code is very important to make full systems work. After reading a recent blog about reddit's structure, it made me question if there is some standard or "accepted systems" out there. I have looked into frameworks (I've used Kohana, which I regretted, but decided that PHP frameworks were not for me) and I prefer my own library of functions rather than having a framework. My current structure is a mix between WordPress, Kohana and my own knowledge. The ways I can see as being potentially beneficial are: Read blogs Read tutorials Work with someone else Read a book What would be the best way(s) to "get to the next level" the level of being a very good system developer?

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  • Given a 2d array sorted in increasing order from left to right and top to bottom, what is the best w

    - by Phukab
    I was recently given this interview question and I'm curious what a good solution to it would be. Say I'm given a 2d array where all the numbers in the array are in increasing order from left to right and top to bottom. What is the best way to search and determine if a target number is in the array? Now, my first inclination is to utilize a binary search since my data is sorted. I can determine if a number is in a single row in O(log N) time. However, it is the 2 directions that throw me off. Another solution I could use, if I could be sure the matrix is n x n, is to start at the middle. If the middle value is less than my target, then I can be sure it is in the left square portion of the matrix from the middle. I then move diagnally and check again, reducing the size of the square that the target could potentially be in until I have honed in on the target number. Does anyone have any good ideas on solving this problem? Example array: Sorted left to right, top to bottom. 1 2 4 5 6 2 3 5 7 8 4 6 8 9 10 5 8 9 10 11

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  • How to structure Javascript programs in complex web applications?

    - by mixedpickles
    Hi there. I have a problem, which is not easily described. I'm writing a web application that makes heavy usage of jquery and ajax calls. Now I don't have experience in designing the architecture for javascript programms, but I realize that my program has not a good structure. I think I have to many identifiers referring to the same (at least more or less) thing. Let's have an exemplary look at an arbitrary UI widget: The eventhandlers use DOM elements as parameters. The DOM element represents a widget in the browser. A lot of times I use jQuery objects (I think they are basically a wrapper around DOM elements) to do something with the widget. Sometimes they are used transiently, sometimes they are stored in a variable for later purposes. The ajax function calls use strings identifiers for these widgets. They are processed server side. Beside that I have a widget class whose instances represents a widget. It is instantiated through the new operator. Now I have somehow four different object identifiers for the same thing, which needs to be kept in sync until the page is loaded anew. This seems not to be a good thing. Any advice?

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  • Credit card validation with regexp using test()

    - by Matt
    I'm trying to complete some homework and it appears the book might have gotten it wrong. I have a simple html page that allows user to pick a credit card in our case american express. The user then enters a number and evalutes that number based on a regular expression. My question ends up being when test() evaluates the number it returns a boolean or a string? I should then compare that string or boolean? True == true should fire off the code in a nested if statement. Heres what the book gives me as valid code: if(document.forms[0].cardName.value == "American Express") { var cardProtocol = new RegExp("^3[47][0-9]{13}$"); //REGEX ENTRY HERE if(cardProtocol.test(document.forms[0].cardNumber.value)) document.forms[0].ccResult.value = "Valid credit card number"; } The above code doesn't work in firefox. I've tried modifying it with 2 alerts to make sure the number is good and the boolean is good...and still no luck: if(document.forms[0].cardName.value == "American Express") { var cardProtocol = new RegExp("^3[47][0-9]{13}$"); //REGEX ENTRY HERE <------ alert(document.forms[0].cardNumber.value) alert(cardProtocol.test(document.forms[0].cardNumber.value)) if((cardProtocol.test(document.forms[0].cardNumber.value)) == true ) // <--Problem { document.forms[0].ccResult.value = "Valid credit card number"; } else { document.forms[0].ccResult.value = "Invalid credit card number"; } } Any ideas? the if loop is the culprit but I'm not figuring out why it is not working. Please throw up the code for the if loop! Thanks for the help!

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  • Java vs. C variant for desktop and tablet development

    - by MirroredFate
    I am going to write a desktop application, but I am conflicted concerning which language to use. It (the desktop application) will need to have a good GUI, and to be extendable (hopefully good with modules of some sort). It must be completely cross-platform, including executable in various tablet environments. I put this as a requirement while realizing that some modification will no doubt be necessary. The language should also have some form of networking tools available. I have read http://introcs.cs.princeton.edu/java/faq/c2java.html and understand the differences between Java and C very well. I am looking not necessarily at C, but more at a C variant. If it is a complete toss-up, I will use Java as I know Java much better. However, I do not want to use a language that will be inferior for the task I wish to accomplish. Thank you for all suggestions and explanations. NOTE: If this is not the correct stack for this question, I apologize. It seemed appropriate according to the rules.

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  • Mercurial on shared network drive?

    - by user1164199
    Right now I have my repo on my local drive. In order to back it up, I have to copy .hg to a window's network drive. At Is it a good idea to put Mercurial Repository in shared Network drive?, Lasse Karlsen said the repo shouldn't be on a shared folder on a network server because "mercurial cannot reliably hold locks in all situations". Would this still be an issue when the repository is only updated by a single user? If so, can someone explain to me why the corruption happens? A while back our IT had problem setting up a mercurial server. I am very fond of mercurial (it has a great interface and is very easy to work with), but if it's going to be such a pain in the neck to set up for multiple users, I am willing to look for something else. Does anyone have any suggestions (with reasons)? I am looking for a revision control program that has the following attributes: 2. Good interface (allow you to easily see revision and changes to the code over multiple revisions). 3. Work as a local repo or a network repo. 4. IT will feel comfortable installing on their network. Thanks, Stephen

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  • Should I Teach My Son Programming? What approaches should I take? [closed]

    - by DaveDev
    I was wondering if it's a good idea to teach object oriented programming to my son? I was never really good at math as a kid, but I think since I've started programming it's given me a greater ability to understand math by being better able to visualise relationships between abstract models. I thought it might give him a better advantage in learning & applying logical & mathematical concepts throughout his life if he was able to take advantage of the tools available to programmers. what would be the best programming fields, techniques and/or concepts? What approach should I take? what concepts should I avoid? what fields of mathematics would he find this benfits him most? He's only 2 now so it wouldn't be for another few years before I do this, (and even at that, only from a very high level point of view). I thought I'd put it to the programming community and see what you guys thought? Possible Duplicate: What are some recommended programming resources for pre-teens?

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  • Book Recomendations: WPF/Silverlight for Business(smallish, internal) Environment

    - by Refracted Paladin
    Yes, I know there are an insane amount of Book posts here(SO) but none I believe for my specific need. If there is and I missed it I apologize. I am the only developer at a non-profit organization(~200 employees) where we are a M$ shop and 90% of the things I develop are specific to our company and are internal only. I am given a lot of latitude on how I accomplish my goals so using new technologies is in my best interest. So far I have developed all winform & asp.net applications but I am an expert by NO MEANS. I would now like to focus on XAML driven development(WPF & Silverlight) but I have no idea where to start. I am subscribed to numerous Silverlight blogs and I have went through a few good tutorials however, I would really appreciate a GOOD SOLID book in my hands going forward. I prefer learning books versus reference books and I REALLY would like one from a Business standpoint as well. Shameless, self-promoting is welcomed if you happen to be an author or reviewer for one that meets my criteria. I would, however, prefer that recomendations were based on first-hand experience(no, 'my friend as this awesome book he told me about', please). If more info is needed to provide accurate recomendations please let me know. Thanks

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  • .NET HTML Sanitation for rich HTML Input

    - by Rick Strahl
    Recently I was working on updating a legacy application to MVC 4 that included free form text input. When I set up the new site my initial approach was to not allow any rich HTML input, only simple text formatting that would respect a few simple HTML commands for bold, lists etc. and automatically handles line break processing for new lines and paragraphs. This is typical for what I do with most multi-line text input in my apps and it works very well with very little development effort involved. Then the client sprung another note: Oh by the way we have a bunch of customers (real estate agents) who need to post complete HTML documents. Oh uh! There goes the simple theory. After some discussion and pleading on my part (<snicker>) to try and avoid this type of raw HTML input because of potential XSS issues, the client decided to go ahead and allow raw HTML input anyway. There has been lots of discussions on this subject on StackOverFlow (and here and here) but to after reading through some of the solutions I didn't really find anything that would work even closely for what I needed. Specifically we need to be able to allow just about any HTML markup, with the exception of script code. Remote CSS and Images need to be loaded, links need to work and so. While the 'legit' HTML posted by these agents is basic in nature it does span most of the full gamut of HTML (4). Most of the solutions XSS prevention/sanitizer solutions I found were way to aggressive and rendered the posted output unusable mostly because they tend to strip any externally loaded content. In short I needed a custom solution. I thought the best solution to this would be to use an HTML parser - in this case the Html Agility Pack - and then to run through all the HTML markup provided and remove any of the blacklisted tags and a number of attributes that are prone to JavaScript injection. There's much discussion on whether to use blacklists vs. whitelists in the discussions mentioned above, but I found that whitelists can make sense in simple scenarios where you might allow manual HTML input, but when you need to allow a larger array of HTML functionality a blacklist is probably easier to manage as the vast majority of elements and attributes could be allowed. Also white listing gets a bit more complex with HTML5 and the new proliferation of new HTML tags and most new tags generally don't affect XSS issues directly. Pure whitelisting based on elements and attributes also doesn't capture many edge cases (see some of the XSS cheat sheets listed below) so even with a white list, custom logic is still required to handle many of those edge cases. The Microsoft Web Protection Library (AntiXSS) My first thought was to check out the Microsoft AntiXSS library. Microsoft has an HTML Encoding and Sanitation library in the Microsoft Web Protection Library (formerly AntiXSS Library) on CodePlex, which provides stricter functions for whitelist encoding and sanitation. Initially I thought the Sanitation class and its static members would do the trick for me,but I found that this library is way too restrictive for my needs. Specifically the Sanitation class strips out images and links which rendered the full HTML from our real estate clients completely useless. I didn't spend much time with it, but apparently I'm not alone if feeling this library is not really useful without some way to configure operation. To give you an example of what didn't work for me with the library here's a small and simple HTML fragment that includes script, img and anchor tags. I would expect the script to be stripped and everything else to be left intact. Here's the original HTML:var value = "<b>Here</b> <script>alert('hello')</script> we go. Visit the " + "<a href='http://west-wind.com'>West Wind</a> site. " + "<img src='http://west-wind.com/images/new.gif' /> " ; and the code to sanitize it with the AntiXSS Sanitize class:@Html.Raw(Microsoft.Security.Application.Sanitizer.GetSafeHtmlFragment(value)) This produced a not so useful sanitized string: Here we go. Visit the <a>West Wind</a> site. While it removed the <script> tag (good) it also removed the href from the link and the image tag altogether (bad). In some situations this might be useful, but for most tasks I doubt this is the desired behavior. While links can contain javascript: references and images can 'broadcast' information to a server, without configuration to tell the library what to restrict this becomes useless to me. I couldn't find any way to customize the white list, nor is there code available in this 'open source' library on CodePlex. Using Html Agility Pack for HTML Parsing The WPL library wasn't going to cut it. After doing a bit of research I decided the best approach for a custom solution would be to use an HTML parser and inspect the HTML fragment/document I'm trying to import. I've used the HTML Agility Pack before for a number of apps where I needed an HTML parser without requiring an instance of a full browser like the Internet Explorer Application object which is inadequate in Web apps. In case you haven't checked out the Html Agility Pack before, it's a powerful HTML parser library that you can use from your .NET code. It provides a simple, parsable HTML DOM model to full HTML documents or HTML fragments that let you walk through each of the elements in your document. If you've used the HTML or XML DOM in a browser before you'll feel right at home with the Agility Pack. Blacklist based HTML Parsing to strip XSS Code For my purposes of HTML sanitation, the process involved is to walk the HTML document one element at a time and then check each element and attribute against a blacklist. There's quite a bit of argument of what's better: A whitelist of allowed items or a blacklist of denied items. While whitelists tend to be more secure, they also require a lot more configuration. In the case of HTML5 a whitelist could be very extensive. For what I need, I only want to ensure that no JavaScript is executed, so a blacklist includes the obvious <script> tag plus any tag that allows loading of external content including <iframe>, <object>, <embed> and <link> etc. <form>  is also excluded to avoid posting content to a different location. I also disallow <head> and <meta> tags in particular for my case, since I'm only allowing posting of HTML fragments. There is also some internal logic to exclude some attributes or attributes that include references to JavaScript or CSS expressions. The default tag blacklist reflects my use case, but is customizable and can be added to. Here's my HtmlSanitizer implementation:using System.Collections.Generic; using System.IO; using System.Xml; using HtmlAgilityPack; namespace Westwind.Web.Utilities { public class HtmlSanitizer { public HashSet<string> BlackList = new HashSet<string>() { { "script" }, { "iframe" }, { "form" }, { "object" }, { "embed" }, { "link" }, { "head" }, { "meta" } }; /// <summary> /// Cleans up an HTML string and removes HTML tags in blacklist /// </summary> /// <param name="html"></param> /// <returns></returns> public static string SanitizeHtml(string html, params string[] blackList) { var sanitizer = new HtmlSanitizer(); if (blackList != null && blackList.Length > 0) { sanitizer.BlackList.Clear(); foreach (string item in blackList) sanitizer.BlackList.Add(item); } return sanitizer.Sanitize(html); } /// <summary> /// Cleans up an HTML string by removing elements /// on the blacklist and all elements that start /// with onXXX . /// </summary> /// <param name="html"></param> /// <returns></returns> public string Sanitize(string html) { var doc = new HtmlDocument(); doc.LoadHtml(html); SanitizeHtmlNode(doc.DocumentNode); //return doc.DocumentNode.WriteTo(); string output = null; // Use an XmlTextWriter to create self-closing tags using (StringWriter sw = new StringWriter()) { XmlWriter writer = new XmlTextWriter(sw); doc.DocumentNode.WriteTo(writer); output = sw.ToString(); // strip off XML doc header if (!string.IsNullOrEmpty(output)) { int at = output.IndexOf("?>"); output = output.Substring(at + 2); } writer.Close(); } doc = null; return output; } private void SanitizeHtmlNode(HtmlNode node) { if (node.NodeType == HtmlNodeType.Element) { // check for blacklist items and remove if (BlackList.Contains(node.Name)) { node.Remove(); return; } // remove CSS Expressions and embedded script links if (node.Name == "style") { if (string.IsNullOrEmpty(node.InnerText)) { if (node.InnerHtml.Contains("expression") || node.InnerHtml.Contains("javascript:")) node.ParentNode.RemoveChild(node); } } // remove script attributes if (node.HasAttributes) { for (int i = node.Attributes.Count - 1; i >= 0; i--) { HtmlAttribute currentAttribute = node.Attributes[i]; var attr = currentAttribute.Name.ToLower(); var val = currentAttribute.Value.ToLower(); span style="background: white; color: green">// remove event handlers if (attr.StartsWith("on")) node.Attributes.Remove(currentAttribute); // remove script links else if ( //(attr == "href" || attr== "src" || attr == "dynsrc" || attr == "lowsrc") && val != null && val.Contains("javascript:")) node.Attributes.Remove(currentAttribute); // Remove CSS Expressions else if (attr == "style" && val != null && val.Contains("expression") || val.Contains("javascript:") || val.Contains("vbscript:")) node.Attributes.Remove(currentAttribute); } } } // Look through child nodes recursively if (node.HasChildNodes) { for (int i = node.ChildNodes.Count - 1; i >= 0; i--) { SanitizeHtmlNode(node.ChildNodes[i]); } } } } } Please note: Use this as a starting point only for your own parsing and review the code for your specific use case! If your needs are less lenient than mine were you can you can make this much stricter by not allowing src and href attributes or CSS links if your HTML doesn't allow it. You can also check links for external URLs and disallow those - lots of options.  The code is simple enough to make it easy to extend to fit your use cases more specifically. It's also quite easy to make this code work using a WhiteList approach if you want to go that route. The code above is semi-generic for allowing full featured HTML fragments that only disallow script related content. The Sanitize method walks through each node of the document and then recursively drills into all of its children until the entire document has been traversed. Note that the code here uses an XmlTextWriter to write output - this is done to preserve XHTML style self-closing tags which are otherwise left as non-self-closing tags. The sanitizer code scans for blacklist elements and removes those elements not allowed. Note that the blacklist is configurable either in the instance class as a property or in the static method via the string parameter list. Additionally the code goes through each element's attributes and looks for a host of rules gleaned from some of the XSS cheat sheets listed at the end of the post. Clearly there are a lot more XSS vulnerabilities, but a lot of them apply to ancient browsers (IE6 and versions of Netscape) - many of these glaring holes (like CSS expressions - WTF IE?) have been removed in modern browsers. What a Pain To be honest this is NOT a piece of code that I wanted to write. I think building anything related to XSS is better left to people who have far more knowledge of the topic than I do. Unfortunately, I was unable to find a tool that worked even closely for me, or even provided a working base. For the project I was working on I had no choice and I'm sharing the code here merely as a base line to start with and potentially expand on for specific needs. It's sad that Microsoft Web Protection Library is currently such a train wreck - this is really something that should come from Microsoft as the systems vendor or possibly a third party that provides security tools. Luckily for my application we are dealing with a authenticated and validated users so the user base is fairly well known, and relatively small - this is not a wide open Internet application that's directly public facing. As I mentioned earlier in the post, if I had my way I would simply not allow this type of raw HTML input in the first place, and instead rely on a more controlled HTML input mechanism like MarkDown or even a good HTML Edit control that can provide some limits on what types of input are allowed. Alas in this case I was overridden and we had to go forward and allow *any* raw HTML posted. Sometimes I really feel sad that it's come this far - how many good applications and tools have been thwarted by fear of XSS (or worse) attacks? So many things that could be done *if* we had a more secure browser experience and didn't have to deal with every little script twerp trying to hack into Web pages and obscure browser bugs. So much time wasted building secure apps, so much time wasted by others trying to hack apps… We're a funny species - no other species manages to waste as much time, effort and resources as we humans do :-) Resources Code on GitHub Html Agility Pack XSS Cheat Sheet XSS Prevention Cheat Sheet Microsoft Web Protection Library (AntiXss) StackOverflow Links: http://stackoverflow.com/questions/341872/html-sanitizer-for-net http://blog.stackoverflow.com/2008/06/safe-html-and-xss/ http://code.google.com/p/subsonicforums/source/browse/trunk/SubSonic.Forums.Data/HtmlScrubber.cs?r=61© Rick Strahl, West Wind Technologies, 2005-2012Posted in Security  HTML  ASP.NET  JavaScript   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Using JSON.NET for dynamic JSON parsing

    - by Rick Strahl
    With the release of ASP.NET Web API as part of .NET 4.5 and MVC 4.0, JSON.NET has effectively pushed out the .NET native serializers to become the default serializer for Web API. JSON.NET is vastly more flexible than the built in DataContractJsonSerializer or the older JavaScript serializer. The DataContractSerializer in particular has been very problematic in the past because it can't deal with untyped objects for serialization - like values of type object, or anonymous types which are quite common these days. The JavaScript Serializer that came before it actually does support non-typed objects for serialization but it can't do anything with untyped data coming in from JavaScript and it's overall model of extensibility was pretty limited (JavaScript Serializer is what MVC uses for JSON responses). JSON.NET provides a robust JSON serializer that has both high level and low level components, supports binary JSON, JSON contracts, Xml to JSON conversion, LINQ to JSON and many, many more features than either of the built in serializers. ASP.NET Web API now uses JSON.NET as its default serializer and is now pulled in as a NuGet dependency into Web API projects, which is great. Dynamic JSON Parsing One of the features that I think is getting ever more important is the ability to serialize and deserialize arbitrary JSON content dynamically - that is without mapping the JSON captured directly into a .NET type as DataContractSerializer or the JavaScript Serializers do. Sometimes it isn't possible to map types due to the differences in languages (think collections, dictionaries etc), and other times you simply don't have the structures in place or don't want to create them to actually import the data. If this topic sounds familiar - you're right! I wrote about dynamic JSON parsing a few months back before JSON.NET was added to Web API and when Web API and the System.Net HttpClient libraries included the System.Json classes like JsonObject and JsonArray. With the inclusion of JSON.NET in Web API these classes are now obsolete and didn't ship with Web API or the client libraries. I re-linked my original post to this one. In this post I'll discus JToken, JObject and JArray which are the dynamic JSON objects that make it very easy to create and retrieve JSON content on the fly without underlying types. Why Dynamic JSON? So, why Dynamic JSON parsing rather than strongly typed parsing? Since applications are interacting more and more with third party services it becomes ever more important to have easy access to those services with easy JSON parsing. Sometimes it just makes lot of sense to pull just a small amount of data out of large JSON document received from a service, because the third party service isn't directly related to your application's logic most of the time - and it makes little sense to map the entire service structure in your application. For example, recently I worked with the Google Maps Places API to return information about businesses close to me (or rather the app's) location. The Google API returns a ton of information that my application had no interest in - all I needed was few values out of the data. Dynamic JSON parsing makes it possible to map this data, without having to map the entire API to a C# data structure. Instead I could pull out the three or four values I needed from the API and directly store it on my business entities that needed to receive the data - no need to map the entire Maps API structure. Getting JSON.NET The easiest way to use JSON.NET is to grab it via NuGet and add it as a reference to your project. You can add it to your project with: PM> Install-Package Newtonsoft.Json From the Package Manager Console or by using Manage NuGet Packages in your project References. As mentioned if you're using ASP.NET Web API or MVC 4 JSON.NET will be automatically added to your project. Alternately you can also go to the CodePlex site and download the latest version including source code: http://json.codeplex.com/ Creating JSON on the fly with JObject and JArray Let's start with creating some JSON on the fly. It's super easy to create a dynamic object structure with any of the JToken derived JSON.NET objects. The most common JToken derived classes you are likely to use are JObject and JArray. JToken implements IDynamicMetaProvider and so uses the dynamic  keyword extensively to make it intuitive to create object structures and turn them into JSON via dynamic object syntax. Here's an example of creating a music album structure with child songs using JObject for the base object and songs and JArray for the actual collection of songs:[TestMethod] public void JObjectOutputTest() { // strong typed instance var jsonObject = new JObject(); // you can explicitly add values here using class interface jsonObject.Add("Entered", DateTime.Now); // or cast to dynamic to dynamically add/read properties dynamic album = jsonObject; album.AlbumName = "Dirty Deeds Done Dirt Cheap"; album.Artist = "AC/DC"; album.YearReleased = 1976; album.Songs = new JArray() as dynamic; dynamic song = new JObject(); song.SongName = "Dirty Deeds Done Dirt Cheap"; song.SongLength = "4:11"; album.Songs.Add(song); song = new JObject(); song.SongName = "Love at First Feel"; song.SongLength = "3:10"; album.Songs.Add(song); Console.WriteLine(album.ToString()); } This produces a complete JSON structure: { "Entered": "2012-08-18T13:26:37.7137482-10:00", "AlbumName": "Dirty Deeds Done Dirt Cheap", "Artist": "AC/DC", "YearReleased": 1976, "Songs": [ { "SongName": "Dirty Deeds Done Dirt Cheap", "SongLength": "4:11" }, { "SongName": "Love at First Feel", "SongLength": "3:10" } ] } Notice that JSON.NET does a nice job formatting the JSON, so it's easy to read and paste into blog posts :-). JSON.NET includes a bunch of configuration options that control how JSON is generated. Typically the defaults are just fine, but you can override with the JsonSettings object for most operations. The important thing about this code is that there's no explicit type used for holding the values to serialize to JSON. Rather the JSON.NET objects are the containers that receive the data as I build up my JSON structure dynamically, simply by adding properties. This means this code can be entirely driven at runtime without compile time restraints of structure for the JSON output. Here I use JObject to create a album 'object' and immediately cast it to dynamic. JObject() is kind of similar in behavior to ExpandoObject in that it allows you to add properties by simply assigning to them. Internally, JObject values are stored in pseudo collections of key value pairs that are exposed as properties through the IDynamicMetaObject interface exposed in JSON.NET's JToken base class. For objects the syntax is very clean - you add simple typed values as properties. For objects and arrays you have to explicitly create new JObject or JArray, cast them to dynamic and then add properties and items to them. Always remember though these values are dynamic - which means no Intellisense and no compiler type checking. It's up to you to ensure that the names and values you create are accessed consistently and without typos in your code. Note that you can also access the JObject instance directly (not as dynamic) and get access to the underlying JObject type. This means you can assign properties by string, which can be useful for fully data driven JSON generation from other structures. Below you can see both styles of access next to each other:// strong type instance var jsonObject = new JObject(); // you can explicitly add values here jsonObject.Add("Entered", DateTime.Now); // expando style instance you can just 'use' properties dynamic album = jsonObject; album.AlbumName = "Dirty Deeds Done Dirt Cheap"; JContainer (the base class for JObject and JArray) is a collection so you can also iterate over the properties at runtime easily:foreach (var item in jsonObject) { Console.WriteLine(item.Key + " " + item.Value.ToString()); } The functionality of the JSON objects are very similar to .NET's ExpandObject and if you used it before, you're already familiar with how the dynamic interfaces to the JSON objects works. Importing JSON with JObject.Parse() and JArray.Parse() The JValue structure supports importing JSON via the Parse() and Load() methods which can read JSON data from a string or various streams respectively. Essentially JValue includes the core JSON parsing to turn a JSON string into a collection of JsonValue objects that can be then referenced using familiar dynamic object syntax. Here's a simple example:public void JValueParsingTest() { var jsonString = @"{""Name"":""Rick"",""Company"":""West Wind"", ""Entered"":""2012-03-16T00:03:33.245-10:00""}"; dynamic json = JValue.Parse(jsonString); // values require casting string name = json.Name; string company = json.Company; DateTime entered = json.Entered; Assert.AreEqual(name, "Rick"); Assert.AreEqual(company, "West Wind"); } The JSON string represents an object with three properties which is parsed into a JObject class and cast to dynamic. Once cast to dynamic I can then go ahead and access the object using familiar object syntax. Note that the actual values - json.Name, json.Company, json.Entered - are actually of type JToken and I have to cast them to their appropriate types first before I can do type comparisons as in the Asserts at the end of the test method. This is required because of the way that dynamic types work which can't determine the type based on the method signature of the Assert.AreEqual(object,object) method. I have to either assign the dynamic value to a variable as I did above, or explicitly cast ( (string) json.Name) in the actual method call. The JSON structure can be much more complex than this simple example. Here's another example of an array of albums serialized to JSON and then parsed through with JsonValue():[TestMethod] public void JsonArrayParsingTest() { var jsonString = @"[ { ""Id"": ""b3ec4e5c"", ""AlbumName"": ""Dirty Deeds Done Dirt Cheap"", ""Artist"": ""AC/DC"", ""YearReleased"": 1976, ""Entered"": ""2012-03-16T00:13:12.2810521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/61kTaH-uZBL._AA115_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/gp/product/…ASIN=B00008BXJ4"", ""Songs"": [ { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Dirty Deeds Done Dirt Cheap"", ""SongLength"": ""4:11"" }, { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Love at First Feel"", ""SongLength"": ""3:10"" }, { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Big Balls"", ""SongLength"": ""2:38"" } ] }, { ""Id"": ""7b919432"", ""AlbumName"": ""End of the Silence"", ""Artist"": ""Henry Rollins Band"", ""YearReleased"": 1992, ""Entered"": ""2012-03-16T00:13:12.2800521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/51FO3rb1tuL._SL160_AA160_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/End-Silence-Rollins-Band/dp/B0000040OX/ref=sr_1_5?ie=UTF8&qid=1302232195&sr=8-5"", ""Songs"": [ { ""AlbumId"": ""7b919432"", ""SongName"": ""Low Self Opinion"", ""SongLength"": ""5:24"" }, { ""AlbumId"": ""7b919432"", ""SongName"": ""Grip"", ""SongLength"": ""4:51"" } ] } ]"; JArray jsonVal = JArray.Parse(jsonString) as JArray; dynamic albums = jsonVal; foreach (dynamic album in albums) { Console.WriteLine(album.AlbumName + " (" + album.YearReleased.ToString() + ")"); foreach (dynamic song in album.Songs) { Console.WriteLine("\t" + song.SongName); } } Console.WriteLine(albums[0].AlbumName); Console.WriteLine(albums[0].Songs[1].SongName); } JObject and JArray in ASP.NET Web API Of course these types also work in ASP.NET Web API controller methods. If you want you can accept parameters using these object or return them back to the server. The following contrived example receives dynamic JSON input, and then creates a new dynamic JSON object and returns it based on data from the first:[HttpPost] public JObject PostAlbumJObject(JObject jAlbum) { // dynamic input from inbound JSON dynamic album = jAlbum; // create a new JSON object to write out dynamic newAlbum = new JObject(); // Create properties on the new instance // with values from the first newAlbum.AlbumName = album.AlbumName + " New"; newAlbum.NewProperty = "something new"; newAlbum.Songs = new JArray(); foreach (dynamic song in album.Songs) { song.SongName = song.SongName + " New"; newAlbum.Songs.Add(song); } return newAlbum; } The raw POST request to the server looks something like this: POST http://localhost/aspnetwebapi/samples/PostAlbumJObject HTTP/1.1User-Agent: FiddlerContent-type: application/jsonHost: localhostContent-Length: 88 {AlbumName: "Dirty Deeds",Songs:[ { SongName: "Problem Child"},{ SongName: "Squealer"}]} and the output that comes back looks like this: {  "AlbumName": "Dirty Deeds New",  "NewProperty": "something new",  "Songs": [    {      "SongName": "Problem Child New"    },    {      "SongName": "Squealer New"    }  ]} The original values are echoed back with something extra appended to demonstrate that we're working with a new object. When you receive or return a JObject, JValue, JToken or JArray instance in a Web API method, Web API ignores normal content negotiation and assumes your content is going to be received and returned as JSON, so effectively the parameter and result type explicitly determines the input and output format which is nice. Dynamic to Strong Type Mapping You can also map JObject and JArray instances to a strongly typed object, so you can mix dynamic and static typing in the same piece of code. Using the 2 Album jsonString shown earlier, the code below takes an array of albums and picks out only a single album and casts that album to a static Album instance.[TestMethod] public void JsonParseToStrongTypeTest() { JArray albums = JArray.Parse(jsonString) as JArray; // pick out one album JObject jalbum = albums[0] as JObject; // Copy to a static Album instance Album album = jalbum.ToObject<Album>(); Assert.IsNotNull(album); Assert.AreEqual(album.AlbumName,jalbum.Value<string>("AlbumName")); Assert.IsTrue(album.Songs.Count > 0); } This is pretty damn useful for the scenario I mentioned earlier - you can read a large chunk of JSON and dynamically walk the property hierarchy down to the item you want to access, and then either access the specific item dynamically (as shown earlier) or map a part of the JSON to a strongly typed object. That's very powerful if you think about it - it leaves you in total control to decide what's dynamic and what's static. Strongly typed JSON Parsing With all this talk of dynamic let's not forget that JSON.NET of course also does strongly typed serialization which is drop dead easy. Here's a simple example on how to serialize and deserialize an object with JSON.NET:[TestMethod] public void StronglyTypedSerializationTest() { // Demonstrate deserialization from a raw string var album = new Album() { AlbumName = "Dirty Deeds Done Dirt Cheap", Artist = "AC/DC", Entered = DateTime.Now, YearReleased = 1976, Songs = new List<Song>() { new Song() { SongName = "Dirty Deeds Done Dirt Cheap", SongLength = "4:11" }, new Song() { SongName = "Love at First Feel", SongLength = "3:10" } } }; // serialize to string string json2 = JsonConvert.SerializeObject(album,Formatting.Indented); Console.WriteLine(json2); // make sure we can serialize back var album2 = JsonConvert.DeserializeObject<Album>(json2); Assert.IsNotNull(album2); Assert.IsTrue(album2.AlbumName == "Dirty Deeds Done Dirt Cheap"); Assert.IsTrue(album2.Songs.Count == 2); } JsonConvert is a high level static class that wraps lower level functionality, but you can also use the JsonSerializer class, which allows you to serialize/parse to and from streams. It's a little more work, but gives you a bit more control. The functionality available is easy to discover with Intellisense, and that's good because there's not a lot in the way of documentation that's actually useful. Summary JSON.NET is a pretty complete JSON implementation with lots of different choices for JSON parsing from dynamic parsing to static serialization, to complex querying of JSON objects using LINQ. It's good to see this open source library getting integrated into .NET, and pushing out the old and tired stock .NET parsers so that we finally have a bit more flexibility - and extensibility - in our JSON parsing. Good to go! Resources Sample Test Project http://json.codeplex.com/© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  Web Api  AJAX   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • SQLAuthority News – SQLPASS Nov 8-11, 2010-Seattle – An Alternative Look at Experience

    - by pinaldave
    I recently attended most prestigious SQL Server event SQLPASS between Nov 8-11, 2010 at Seattle. I have only one expression for the event - Best Summit Ever This year the summit was at its best. Instead of writing about my usual routine or the event, I am going to write about the interesting things I did and how I felt about it! Best Summit Ever Trip to Seattle! This was my second trip to Seattle this year and the journey is always long. Here is the travel stats on how long it takes to get to Seattle: 24 hours official air time 36 hours total travel time (connection waits and airport commute) Every time I travel to USA I gain a day and when I travel back to home, I lose a day. However, the total traveling time is around 3 days. The journey is long and very exhausting. However, it is all worth it when you’re attending an event like SQLPASS. Here are few things I carry when I travel for a long journey: Dry Snack packs – I like to have some good Indian Dry Snacks along with me in my backpack so I can have my own snack when I want Amazon Kindle – Loaded with 80+ books A physical book – This is usually a very easy to read book I do not watch movies on the plane and usually spend my time reading something quick and easy. If I can go to sleep, I go for it. I prefer to not to spend time in conversation with the guy sitting next to me because usually I end up listening to their biography, which I cannot blog about. Sheraton Seattle SQLPASS In any case, I love to go to Seattle as the city is great and has everything a brilliant metropolis has to offer. The new Light Train is extremely convenient, and I can take it directly from the airport to the city center. My hotel, the Sheraton, was only few meters (in the USA people count in blocks – 3 blocks) away from the train station. This time I saved USD 40 each round trip due to the Light Train. Sessions I attended! Well, I really wanted to attend most of the sessions but there was great dilemma of which ones to choose. There were many, many sessions to be attended and at any given time there was more than one good session being presented. I had decided to attend sessions in area performance tuning and I attended quite a few sessions this year, compared to what I was able to do last year. Here are few names of the speakers whose sessions I attended (please note, following great speakers are not listed in any order. I loved them and I enjoyed their sessions): Conor Cunningham Rushabh Mehta Buck Woody Brent Ozar Jonathan Kehayias Chris Leonard Bob Ward Grant Fritchey I had great fun attending their sessions. The sessions were meaningful and enlightening. It is hard to rate any session but I have found that the insights learned in Conor Cunningham’s sessions are the highlight of the PASS Summit. Rushabh Mehta at Keynote SQLPASS   Bucky Woody and Brent Ozar I always like the sessions where the speaker is much closer to the audience and has real world experience. I think speakers who have worked in the real world deliver the best content and most useful information. Sessions I did not like! Indeed there were few sessions I did not like it and I am not going to name them here. However, there were strong reasons I did not like their sessions, and here is why: Sessions were all theory and had no real world connections. All technical questions ended with confusing answers (lots of “I will get back to you on it,” “it depends,” “let us take this offline” and many more…) “I am God” kind of attitude in the speakers For example, I attended a session of one very well known speaker who is a specialist for one particular area. I was bit late for the session and was surprised to see that in a room that could hold 350 people there were only 30 attendees. After sitting there for 15 minutes, I realized why lots of people left. Very soon I found I preferred to stare out the window instead of listening to that particular speaker. One on One Talk! Many times people ask me what I really like about PASS. I always say the experience of meeting SQL legends and spending time with them one on one and LEARNING! Here is the quick list of the people I met during this event and spent more than 30 minutes with each of them talking about various subjects: Pinal Dave and Brad Shulz Pinal Dave and Rushabh Mehta Michael Coles and Pinal Dave Rushabh Mehta – It is always pleasure to meet with him. He is a man with lots of energy and a passion for community. He recently told me that he really wanted to turn PASS into resource for learning for every SQL Server Developer and Administrator in the world. I had great in-depth discussion regarding how a single person can contribute to a community. Michael Coles – I consider him my best friend. It is always fun to meet him. He is funny and very knowledgeable. I think there are very few people who are as expert as he is in encryption and spatial databases. Worth meeting him every single time. Glenn Berry – A real friend of everybody. He is very a simple person and very true to his heart. I think there is not a single person in whole community who does not like him. He is a friends of all and everybody likes him very much. I once again had time to sit with him and learn so much from him. As he is known as Dr. DMV, I can be his nurse in the area of DMV. Brad Schulz – I always wanted to meet him but never got chance until today. I had great time meeting him in person and we have spent considerable amount of time together discussing various T-SQL tricks and tips. I do not know where he comes up with all the different ideas but I enjoy reading his blog and sharing his wisdom with me. Jonathan Kehayias – He is drill sergeant in US army. If you get the impression that he is a giant with very strong personality – you are wrong. He is very kind and soft spoken DBA with strong performance tuning skills. I asked him how he has kept his two jobs separate and I got very good answer – just work hard and have passion for what you do. I attended his sessions and his presentation style is very unique.  I feel like he is speaking in a language I understand. Louis Davidson – I had never had a chance to sit with him and talk about technology before. He has so much wisdom and he is very kind. During the dinner, I had talked with him for long time and without hesitation he started to draw a schema for me on the menu. It was a wonderful experience to learn from a master at the dinner table. He explained to me the real and practical differences between third normal form and forth normal form. Honestly I did not know earlier, but now I do. Erland Sommarskog – This man needs no introduction, he is very well known and very clear in conveying his ideas. I learned a lot from him during the course of year. Every time I meet him, I learn something new and this time was no exception. Joe Webb – Joey is all about community and people, we had interesting conversation about community, MVP and how one can be helpful to community without losing passion for long time. It is always pleasant to talk to him and of course, I had fun time. Ross Mistry – I call him my brother many times because he indeed looks like my cousin. He provided me lots of insight of how one can write book and how he keeps his books simple to appeal to all the readers. A wonderful person and great friend. Ola Hallgren - I did not know he was coming to the summit. I had great time meeting him and had a wonderful conversation with him regarding his scripts and future community activities. Blythe Morrow – She used to be integrated part of SQL Server Community and PASS HQ. It was wonderful to meet her again and re-connect. She is wonderful person and I had a great time talking to her. Solid Quality Mentors – It is difficult to decide who to mention here. Instead of writing all the names, I am going to include a photo of our meeting. I had great fun meeting various members of our global branches. This year I was sitting with my Spanish speaking friends and had great fun as Javier Loria from Solid Quality translated lots of things for me. Party, Party and Parties Every evening there were various parties. I did attend almost all of them. Every party had different theme but the goal of all the parties the same – networking. Here are the few parties where I had lots of fun: Dell Reception Party Exhibitor Party Solid Quality Fun Party Red Gate Friends Party MVP Dinner Microsoft Party MVP Dinner Quest Party Gameworks PASS Party Volunteer Party at Garage Solid Quality Mentors (10 Members out of 120) They were all great networking opportunities and lots of fun. I really had great time meeting people at the various parties. There were few people everywhere – well, I will say I am among them – who hopped parties. NDA – Not Decided Agenda During the event there were few meetings marked “NDA.” Someone asked me “why are these things NDA?”  My response was simple: because they are not sure themselves. NDA stands for Not Decided Agenda. Toys, Giveaways and Luggage I admit, I was like child in Gameworks and was playing to win soft toys. I was doing it for my daughter. I must thank all of the people who gave me their cards to try my luck. I won 4 soft-toys for my daughter and it was fun. Also, thanks to Angel who did a final toy swap with me to get the desired toy for my daughter. I also collected ducks from Idera, as my daughter really loves them. Solid Quality Booth Each of the exhibitors was giving away something and I got so much stuff that my luggage got quite a bit bigger when I returned. Best Exhibitor Idera had SQLDoctor (a real magician and fun guy) to promote their new tool SQLDoctor. I really had a great time participating in the magic myself. At one point, the magician made my watch disappear.  I have seen better magic before, but this time it caught me unexpectedly and I was taken by surprise. I won many ducks again. The Common Question I heard the following common questions: I have seen you somewhere – who are you? – I am Pinal Dave. I did not know that Pinal is your first name and Dave is your last name, how do you pronounce your last name again? – Da-way How old are you? – I am as old as I can be. Are you an Indian because you look like one? – I did not answer this one. Where are you from? This question was usually asked after looking at my badge which says India. So did you really fly from India? – Yes, because I have seasickness so I do not prefer the sea journey. How long was the journey? – 24/36/12 (air travel time/total travel time/time zone difference) Why do you write on SQLAuthority.com? – Because I want to. I remember your daughter looks like you. – Is this even a question? Of course, she is daddy’s little girl. There were so many other questions, I will have to write another blog post about it. SQLPASS Again, Best Summit Ever! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: About Me, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology Tagged: SQLPASS

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  • SQL Monitor’s data repository: Alerts

    - by Chris Lambrou
    In my previous post, I introduced the SQL Monitor data repository, and described how the monitored objects are stored in a hierarchy in the data schema, in a series of tables with a _Keys suffix. In this post I had planned to describe how the actual data for the monitored objects is stored in corresponding tables with _StableSamples and _UnstableSamples suffixes. However, I’m going to postpone that until my next post, as I’ve had a request from a SQL Monitor user to explain how alerts are stored. In the SQL Monitor data repository, alerts are stored in tables belonging to the alert schema, which contains the following five tables: alert.Alert alert.Alert_Cleared alert.Alert_Comment alert.Alert_Severity alert.Alert_Type In this post, I’m only going to cover the alert.Alert and alert.Alert_Type tables. I may cover the other three tables in a later post. The most important table in this schema is alert.Alert, as each row in this table corresponds to a single alert. So let’s have a look at it. SELECT TOP 100 AlertId, AlertType, TargetObject, [Read], SubType FROM alert.Alert ORDER BY AlertId DESC;  AlertIdAlertTypeTargetObjectReadSubType 165550397:Cluster,1,4:Name,s29:srp-mr03.testnet.red-gate.com,9:SqlServer,1,4:Name,s0:,10 265549387:Cluster,1,4:Name,s29:srp-mr03.testnet.red-gate.com,7:Machine,1,4:Name,s0:,10 365548187:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s15:FavouriteThings,00 465547157:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s15:FavouriteThings,00 565546147:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s15:FavouriteThings,00 665545187:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s14:SqlMonitorData,00 765544157:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s14:SqlMonitorData,00 865543147:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s14:SqlMonitorData,00 965542187:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s4:msdb,00 1065541147:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s4:msdb,00 11…     So what are we seeing here, then? Well, AlertId is an auto-incrementing identity column, so ORDER BY AlertId DESC ensures that we see the most recent alerts first. AlertType indicates the type of each alert, such as Job failed (6), Backup overdue (14) or Long-running query (12). The TargetObject column indicates which monitored object the alert is associated with. The Read column acts as a flag to indicate whether or not the alert has been read. And finally the SubType column is used in the case of a Custom metric (40) alert, to indicate which custom metric the alert pertains to. Okay, now lets look at some of those columns in more detail. The AlertType column is an easy one to start with, and it brings use nicely to the next table, data.Alert_Type. Let’s have a look at what’s in this table: SELECT AlertType, Event, Monitoring, Name, Description FROM alert.Alert_Type ORDER BY AlertType;  AlertTypeEventMonitoringNameDescription 1100Processor utilizationProcessor utilization (CPU) on a host machine stays above a threshold percentage for longer than a specified duration 2210SQL Server error log entryAn error is written to the SQL Server error log with a severity level above a specified value. 3310Cluster failoverThe active cluster node fails, causing the SQL Server instance to switch nodes. 4410DeadlockSQL deadlock occurs. 5500Processor under-utilizationProcessor utilization (CPU) on a host machine remains below a threshold percentage for longer than a specified duration 6610Job failedA job does not complete successfully (the job returns an error code). 7700Machine unreachableHost machine (Windows server) cannot be contacted on the network. 8800SQL Server instance unreachableThe SQL Server instance is not running or cannot be contacted on the network. 9900Disk spaceDisk space used on a logical disk drive is above a defined threshold for longer than a specified duration. 101000Physical memoryPhysical memory (RAM) used on the host machine stays above a threshold percentage for longer than a specified duration. 111100Blocked processSQL process is blocked for longer than a specified duration. 121200Long-running queryA SQL query runs for longer than a specified duration. 131400Backup overdueNo full backup exists, or the last full backup is older than a specified time. 141500Log backup overdueNo log backup exists, or the last log backup is older than a specified time. 151600Database unavailableDatabase changes from Online to any other state. 161700Page verificationTorn Page Detection or Page Checksum is not enabled for a database. 171800Integrity check overdueNo entry for an integrity check (DBCC DBINFO returns no date for dbi_dbccLastKnownGood field), or the last check is older than a specified time. 181900Fragmented indexesFragmentation level of one or more indexes is above a threshold percentage. 192400Job duration unusualThe duration of a SQL job duration deviates from its baseline duration by more than a threshold percentage. 202501Clock skewSystem clock time on the Base Monitor computer differs from the system clock time on a monitored SQL Server host machine by a specified number of seconds. 212700SQL Server Agent Service statusThe SQL Server Agent Service status matches the status specified. 222800SQL Server Reporting Service statusThe SQL Server Reporting Service status matches the status specified. 232900SQL Server Full Text Search Service statusThe SQL Server Full Text Search Service status matches the status specified. 243000SQL Server Analysis Service statusThe SQL Server Analysis Service status matches the status specified. 253100SQL Server Integration Service statusThe SQL Server Integration Service status matches the status specified. 263300SQL Server Browser Service statusThe SQL Server Browser Service status matches the status specified. 273400SQL Server VSS Writer Service statusThe SQL Server VSS Writer status matches the status specified. 283501Deadlock trace flag disabledThe monitored SQL Server’s trace flag cannot be enabled. 293600Monitoring stopped (host machine credentials)SQL Monitor cannot contact the host machine because authentication failed. 303700Monitoring stopped (SQL Server credentials)SQL Monitor cannot contact the SQL Server instance because authentication failed. 313800Monitoring error (host machine data collection)SQL Monitor cannot collect data from the host machine. 323900Monitoring error (SQL Server data collection)SQL Monitor cannot collect data from the SQL Server instance. 334000Custom metricThe custom metric value has passed an alert threshold. 344100Custom metric collection errorSQL Monitor cannot collect custom metric data from the target object. Basically, alert.Alert_Type is just a big reference table containing information about the 34 different alert types supported by SQL Monitor (note that the largest id is 41, not 34 – some alert types have been retired since SQL Monitor was first developed). The Name and Description columns are self evident, and I’m going to skip over the Event and Monitoring columns as they’re not very interesting. The AlertId column is the primary key, and is referenced by AlertId in the alert.Alert table. As such, we can rewrite our earlier query to join these two tables, in order to provide a more readable view of the alerts: SELECT TOP 100 AlertId, Name, TargetObject, [Read], SubType FROM alert.Alert a JOIN alert.Alert_Type at ON a.AlertType = at.AlertType ORDER BY AlertId DESC;  AlertIdNameTargetObjectReadSubType 165550Monitoring error (SQL Server data collection)7:Cluster,1,4:Name,s29:srp-mr03.testnet.red-gate.com,9:SqlServer,1,4:Name,s0:,00 265549Monitoring error (host machine data collection)7:Cluster,1,4:Name,s29:srp-mr03.testnet.red-gate.com,7:Machine,1,4:Name,s0:,00 365548Integrity check overdue7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s15:FavouriteThings,00 465547Log backup overdue7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s15:FavouriteThings,00 565546Backup overdue7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s15:FavouriteThings,00 665545Integrity check overdue7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s14:SqlMonitorData,00 765544Log backup overdue7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s14:SqlMonitorData,00 865543Backup overdue7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s14:SqlMonitorData,00 965542Integrity check overdue7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s4:msdb,00 1065541Backup overdue7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s4:msdb,00 Okay, the next column to discuss in the alert.Alert table is TargetObject. Oh boy, this one’s a bit tricky! The TargetObject of an alert is a serialized string representation of the position in the monitored object hierarchy of the object to which the alert pertains. The serialization format is somewhat convenient for parsing in the C# source code of SQL Monitor, and has some helpful characteristics, but it’s probably very awkward to manipulate in T-SQL. I could document the serialization format here, but it would be very dry reading, so perhaps it’s best to consider an example from the table above. Have a look at the alert with an AlertID of 65543. It’s a Backup overdue alert for the SqlMonitorData database running on the default instance of granger, my laptop. Each different alert type is associated with a specific type of monitored object in the object hierarchy (I described the hierarchy in my previous post). The Backup overdue alert is associated with databases, whose position in the object hierarchy is root → Cluster → SqlServer → Database. The TargetObject value identifies the target object by specifying the key properties at each level in the hierarchy, thus: Cluster: Name = "granger" SqlServer: Name = "" (an empty string, denoting the default instance) Database: Name = "SqlMonitorData" Well, look at the actual TargetObject value for this alert: "7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s14:SqlMonitorData,". It is indeed composed of three parts, one for each level in the hierarchy: Cluster: "7:Cluster,1,4:Name,s7:granger," SqlServer: "9:SqlServer,1,4:Name,s0:," Database: "8:Database,1,4:Name,s14:SqlMonitorData," Each part is handled in exactly the same way, so let’s concentrate on the first part, "7:Cluster,1,4:Name,s7:granger,". It comprises the following: "7:Cluster," – This identifies the level in the hierarchy. "1," – This indicates how many different key properties there are to uniquely identify a cluster (we saw in my last post that each cluster is identified by a single property, its Name). "4:Name,s14:SqlMonitorData," – This represents the Name property, and its corresponding value, SqlMonitorData. It’s split up like this: "4:Name," – Indicates the name of the key property. "s" – Indicates the type of the key property, in this case, it’s a string. "14:SqlMonitorData," – Indicates the value of the property. At this point, you might be wondering about the format of some of these strings. Why is the string "Cluster" stored as "7:Cluster,"? Well an encoding scheme is used, which consists of the following: "7" – This is the length of the string "Cluster" ":" – This is a delimiter between the length of the string and the actual string’s contents. "Cluster" – This is the string itself. 7 characters. "," – This is a final terminating character that indicates the end of the encoded string. You can see that "4:Name,", "8:Database," and "14:SqlMonitorData," also conform to the same encoding scheme. In the example above, the "s" character is used to indicate that the value of the Name property is a string. If you explore the TargetObject property of alerts in your own SQL Monitor data repository, you might find other characters used for other non-string key property values. The different value types you might possibly encounter are as follows: "I" – Denotes a bigint value. For example, "I65432,". "g" – Denotes a GUID value. For example, "g32116732-63ae-4ab5-bd34-7dfdfb084c18,". "d" – Denotes a datetime value. For example, "d634815384796832438,". The value is stored as a bigint, rather than a native SQL datetime value. I’ll describe how datetime values are handled in the SQL Monitor data repostory in a future post. I suggest you have a look at the alerts in your own SQL Monitor data repository for further examples, so you can see how the TargetObject values are composed for each of the different types of alert. Let me give one further example, though, that represents a Custom metric alert, as this will help in describing the final column of interest in the alert.Alert table, SubType. Let me show you the alert I’m interested in: SELECT AlertId, a.AlertType, Name, TargetObject, [Read], SubType FROM alert.Alert a JOIN alert.Alert_Type at ON a.AlertType = at.AlertType WHERE AlertId = 65769;  AlertIdAlertTypeNameTargetObjectReadSubType 16576940Custom metric7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s6:master,12:CustomMetric,1,8:MetricId,I2,02 An AlertType value of 40 corresponds to the Custom metric alert type. The Name taken from the alert.Alert_Type table is simply Custom metric, but this doesn’t tell us anything about the specific custom metric that this alert pertains to. That’s where the SubType value comes in. For custom metric alerts, this provides us with the Id of the specific custom alert definition that can be found in the settings.CustomAlertDefinitions table. I don’t really want to delve into custom alert definitions yet (maybe in a later post), but an extra join in the previous query shows us that this alert pertains to the CPU pressure (avg runnable task count) custom metric alert. SELECT AlertId, a.AlertType, at.Name, cad.Name AS CustomAlertName, TargetObject, [Read], SubType FROM alert.Alert a JOIN alert.Alert_Type at ON a.AlertType = at.AlertType JOIN settings.CustomAlertDefinitions cad ON a.SubType = cad.Id WHERE AlertId = 65769;  AlertIdAlertTypeNameCustomAlertNameTargetObjectReadSubType 16576940Custom metricCPU pressure (avg runnable task count)7:Cluster,1,4:Name,s7:granger,9:SqlServer,1,4:Name,s0:,8:Database,1,4:Name,s6:master,12:CustomMetric,1,8:MetricId,I2,02 The TargetObject value in this case breaks down like this: "7:Cluster,1,4:Name,s7:granger," – Cluster named "granger". "9:SqlServer,1,4:Name,s0:," – SqlServer named "" (the default instance). "8:Database,1,4:Name,s6:master," – Database named "master". "12:CustomMetric,1,8:MetricId,I2," – Custom metric with an Id of 2. Note that the hierarchy for a custom metric is slightly different compared to the earlier Backup overdue alert. It’s root → Cluster → SqlServer → Database → CustomMetric. Also notice that, unlike Cluster, SqlServer and Database, the key property for CustomMetric is called MetricId (not Name), and the value is a bigint (not a string). Finally, delving into the custom metric tables is beyond the scope of this post, but for the sake of avoiding any future confusion, I’d like to point out that whilst the SubType references a custom alert definition, the MetricID value embedded in the TargetObject value references a custom metric definition. Although in this case both the custom metric definition and custom alert definition share the same Id value of 2, this is not generally the case. Okay, that’s enough for now, not least because as I’m typing this, it’s almost 2am, I have to go to work tomorrow, and my alarm is set for 6am – eek! In my next post, I’ll either cover the remaining three tables in the alert schema, or I’ll delve into the way SQL Monitor stores its monitoring data, as I’d originally planned to cover in this post.

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  • The Windows Store... why did I sign up with this mess again?

    - by FransBouma
    Yesterday, Microsoft revealed that the Windows Store is now open to all developers in a wide range of countries and locations. For the people who think "wtf is the 'Windows Store'?", it's the central place where Windows 8 users will be able to find, download and purchase applications (or as we now have to say to not look like a computer illiterate: <accent style="Kentucky">aaaaappss</accent>) for Windows 8. As this is the store which is integrated into Windows 8, it's an interesting place for ISVs, as potential customers might very well look there first. This of course isn't true for all kinds of software, and developer tools in general aren't the kind of applications most users will download from the Windows store, but a presence there can't hurt. Now, this Windows Store hosts two kinds of applications: 'Metro-style' applications and 'Desktop' applications. The 'Metro-style' applications are applications created for the new 'Metro' UI which is present on Windows 8 desktop and Windows RT (the single color/big font fingerpaint-oriented UI). 'Desktop' applications are the applications we all run and use on Windows today. Our software are desktop applications. The Windows Store hosts all Metro-style applications locally in the store and handles the payment for these applications. This means you upload your application (sorry, 'app') to the store, jump through a lot of hoops, Microsoft verifies that your application is not violating a tremendous long list of rules and after everything is OK, it's published and hopefully you get customers and thus earn money. Money which Microsoft will pay you on a regular basis after customers buy your application. Desktop applications are not following this path however. Desktop applications aren't hosted by the Windows Store. Instead, the Windows Store more or less hosts a page with the application's information and where to get the goods. I.o.w.: it's nothing more than a product's Facebook page. Microsoft will simply redirect a visitor of the Windows Store to your website and the visitor will then use your site's system to purchase and download the application. This last bit of information is very important. So, this morning I started with fresh energy to register our company 'Solutions Design bv' at the Windows Store and our two applications, LLBLGen Pro and ORM Profiler. First I went to the Windows Store dashboard page. If you don't have an account, you have to log in or sign up if you don't have a live account. I signed in with my live account. After that, it greeted me with a page where I had to fill in a code which was mailed to me. My local mail server polls every several minutes for email so I had to kick it to get it immediately. I grabbed the code from the email and I was presented with a multi-step process to register myself as a company or as an individual. In red I was warned that this choice was permanent and not changeable. I chuckled: Microsoft apparently stores its data on paper, not in digital form. I chose 'company' and was presented with a lengthy form to fill out. On the form there were two strange remarks: Per company there can just be 1 (one, uno, not zero, not two or more) registered developer, and only that developer is able to upload stuff to the store. I have no idea how this works with large companies, oh the overhead nightmares... "Sorry, but John, our registered developer with the Windows Store is on holiday for 3 months, backpacking through Australia, no, he's not reachable at this point. M'yeah, sorry bud. Hey, did you fill in those TPS reports yesterday?" A separate Approver has to be specified, which has to be a different person than the registered developer. Apparently to Microsoft a company with just 1 person is not a company. Luckily we're with two people! *pfew*, dodged that one, otherwise I would be stuck forever: the choice I already made was not reversible! After I had filled out the form and it was all well and good and accepted by the Microsoft lackey who had to write it all down in some paper notebook ("Hey, be warned! It's a permanent choice! Written down in ink, can't be changed!"), I was presented with the question how I wanted to pay for all this. "Pay for what?" I wondered. Must be the paper they were scribbling the information on, I concluded. After all, there's a financial crisis going on! How could I forget! Silly me. "Ok fair enough". The price was 75 Euros, not the end of the world. I could only pay by credit card, so it was accepted quickly. Or so I thought. You see, Microsoft has a different idea about CC payments. In the normal world, you type in your CC number, some date, a name and a security code and that's it. But Microsoft wants to verify this even more. They want to make a verification purchase of a very small amount and are doing that with a special code in the description. You then have to type in that code in a special form in the Windows Store dashboard and after that you're verified. Of course they'll refund the small amount they pull from your card. Sounds simple, right? Well... no. The problem starts with the fact that I can't see the CC activity on some website: I have a bank issued CC card. I get the CC activity once a month on a piece of paper sent to me. The bank's online website doesn't show them. So it's possible I have to wait for this code till October 12th. One month. "So what, I'm not going to use it anyway, Desktop applications don't use the payment system", I thought. "Haha, you're so naive, dear developer!" Microsoft won't allow you to publish any applications till this verification is done. So no application publishing for a month. Wouldn't it be nice if things were, you know, digital, so things got done instantly? But of course, that lackey who scribbled everything in the Big Windows Store Registration Book isn't that quick. Can't blame him though. He's just doing his job. Now, after the payment was done, I was presented with a page which tells me Microsoft is going to use a third party company called 'Symantec', which will verify my identity again. The page explains to me that this could be done through email or phone and that they'll contact the Approver to verify my identity. "Phone?", I thought... that's a little drastic for a developer account to publish a single page of information about an external hosted software product, isn't it? On Facebook I just added a page, done. And paying you, Microsoft, took less information: you were happy to take my money before my identity was even 'verified' by this 3rd party's minions! "Double standards!", I roared. No-one cared. But it's the thought of getting it off your chest, you know. Luckily for me, everyone at Symantec was asleep when I was registering so they went for the fallback option in case phone calls were not possible: my Approver received an email. Imagine you have to explain the idiot web of security theater I was caught in to someone else who then has to reply a random person over the internet that I indeed was who I said I was. As she's a true sweetheart, she gave me the benefit of the doubt and assured that for now, I was who I said I was. Remember, this is for a desktop application, which is only a link to a website, some pictures and a piece of text. No file hosting, no payment processing, nothing, just a single page. Yeah, I also thought I was crazy. But we're not at the end of this quest yet. I clicked around in the confusing menus of the Windows Store dashboard and found the 'Desktop' section. I get a helpful screen with a warning in red that it can't find any certified 'apps'. True, I'm just getting started, buddy. I see a link: "Check the Windows apps you submitted for certification". Well, I haven't submitted anything, but let's see where it brings me. Oh the thrill of adventure! I click the link and I end up on this site: the hardware/desktop dashboard account registration. "Erm... but I just registered...", I mumbled to no-one in particular. Apparently for desktop registration / verification I have to register again, it tells me. But not only that, the desktop application has to be signed with a certificate. And not just some random el-cheapo certificate you can get at any mall's discount store. No, this certificate is special. It's precious. This certificate, the 'Microsoft Authenticode' Digital Certificate, is the only certificate that's acceptable, and jolly, it can be purchased from VeriSign for the price of only ... $99.-, but be quick, because this is a limited time offer! After that it's, I kid you not, $499.-. 500 dollars for a certificate to sign an executable. But, I do feel special, I got a special price. Only for me! I'm glowing. Not for long though. Here I started to wonder, what the benefit of it all was. I now again had to pay money for a shiny certificate which will add 'Solutions Design bv' to our installer as the publisher instead of 'unknown', while our customers download the file from our website. Not only that, but this was all about a Desktop application, which wasn't hosted by Microsoft. They only link to it. And make no mistake. These prices aren't single payments. Every year these have to be renewed. Like a membership of an exclusive club: you're special and privileged, but only if you cough up the dough. To give you an example how silly this all is: I added LLBLGen Pro and ORM Profiler to the Visual Studio Gallery some time ago. It's the same thing: it's a central place where one can find software which adds to / extends / works with Visual Studio. I could simply create the pages, add the information and they show up inside Visual Studio. No files are hosted at Microsoft, they're downloaded from our website. Exactly the same system. As I have to wait for the CC transcripts to arrive anyway, I can't proceed with publishing in this new shiny store. After the verification is complete I have to wait for verification of my software by Microsoft. Even Desktop applications need to be verified using a long list of rules which are mainly focused on Metro-style applications. Even while they're not hosted by Microsoft. I wonder what they'll find. "Your application wasn't approved. It violates rule 14 X sub D: it provides more value than our own competing framework". While I was writing this post, I tried to check something in the Windows Store Dashboard, to see whether I remembered it correctly. I was presented again with the question, after logging in with my live account, to enter the code that was just mailed to me. Not the previous code, a brand new one. Again I had to kick my mail server to pull the email to proceed. This was it. This 'experience' is so beyond miserable, I'm afraid I have to say goodbye for now to the 'Windows Store'. It's simply not worth my time. Now, about live accounts. You might know this: live accounts are tied to everything you do with Microsoft. So if you have an MSDN subscription, e.g. the one which costs over $5000.-, it's tied to this same live account. But the fun thing is, you can login with your live account to the MSDN subscriptions with just the account id and password. No additional code is mailed to you. While it gives you access to all Microsoft software available, including your licenses. Why the draconian security theater with this Windows Store, while all I want is to publish some desktop applications while on other Microsoft sites it's OK to simply sign in with your live account: no codes needed, no verification and no certificates? Microsoft, one thing you need with this store and that's: apps. Apps, apps, apps, apps, aaaaaaaaapps. Sorry, my bad, got carried away. I just can't stand the word 'app'. This store's shelves have to be filled to the brim with goods. But instead of being welcomed into the store with open arms, I have to fight an uphill battle with an endless list of rules and bullshit to earn the privilege to publish in this shiny store. As if I have to be thrilled to be one of the exclusive club called 'Windows Store Publishers'. As if Microsoft doesn't want it to succeed. Craig Stuntz sent me a link to an old blog post of his regarding code signing and uploading to Microsoft's old mobile store from back in the WinMo5 days: http://blogs.teamb.com/craigstuntz/2006/10/11/28357/. Good read and good background info about how little things changed over the years. I hope this helps Microsoft make things more clearer and smoother and also helps ISVs with their decision whether to go with the Windows Store scheme or ignore it. For now, I don't see the advantage of publishing there, especially not with the nonsense rules Microsoft cooked up. Perhaps it changes in the future, who knows.

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  • CLSF & CLK 2013 Trip Report by Jeff Liu

    - by jamesmorris
    This is a contributed post from Jeff Liu, lead XFS developer for the Oracle mainline Linux kernel team. Recently, I attended both the China Linux Storage and Filesystem workshop (CLSF), and the China Linux Kernel conference (CLK), which were held in Shanghai. Here are the highlights for both events. CLSF - 17th October XFS update (led by Jeff Liu) XFS keeps rapid progress with a lot of changes, especially focused on the infrastructure/performance improvements as well as  new feature development.  This can be reflected with a sample statistics among XFS/Ext4+JBD2/Btrfs via: # git diff --stat --minimal -C -M v3.7..v3.12-rc4 -- fs/xfs|fs/ext4+fs/jbd2|fs/btrfs XFS: 141 files changed, 27598 insertions(+), 19113 deletions(-) Ext4+JBD2: 39 files changed, 10487 insertions(+), 5454 deletions(-) Btrfs: 70 files changed, 19875 insertions(+), 8130 deletions(-) What made up those changes in XFS? Self-describing metadata(CRC32c). This is a new feature and it contributed about 70% code changes, it can be enabled via `mkfs.xfs -m crc=1 /dev/xxx` for v5 superblock. Transaction log space reservation improvements. With this change, we can calculate the log space reservation at mount time rather than runtime to reduce the the CPU overhead. User namespace support. So both XFS and USERNS can be enabled on kernel configuration begin from Linux 3.10. Thanks Dwight Engen's efforts for this thing. Split project/group quota inodes. Originally, project quota can not be enabled with group quota at the same time because they were share the same quota file inode, now it works but only for v5 super block. i.e, CRC enabled. CONFIG_XFS_WARN, an new lightweight runtime debugger which can be deployed in production environment. Readahead log object recovery, this change can speed up the log replay progress significantly. Speculative preallocation inode tracking, clearing and throttling. The main purpose is to deal with inodes with post-EOF space due to speculative preallocation, support improved quota management to free up a significant amount of unwritten space when at or near EDQUOT. It support backgroup scanning which occurs on a longish interval(5 mins by default, tunable), and on-demand scanning/trimming via ioctl(2). Bitter arguments ensued from this session, especially for the comparison between Ext4 and Btrfs in different areas, I have to spent a whole morning of the 1st day answering those questions. We basically agreed on XFS is the best choice in Linux nowadays because: Stable, XFS has a good record in stability in the past 10 years. Fengguang Wu who lead the 0-day kernel test project also said that he has observed less error than other filesystems in the past 1+ years, I own it to the XFS upstream code reviewer, they always performing serious code review as well as testing. Good performance for large/small files, XFS does not works very well for small files has already been an old story for years. Best choice (maybe) for distributed PB filesystems. e.g, Ceph recommends delopy OSD daemon on XFS because Ext4 has limited xattr size. Best choice for large storage (>16TB). Ext4 does not support a single file more than around 15.95TB. Scalability, any objection to XFS is best in this point? :) XFS is better to deal with transaction concurrency than Ext4, why? The maximum size of the log in XFS is 2038MB compare to 128MB in Ext4. Misc. Ext4 is widely used and it has been proved fast/stable in various loads and scenarios, XFS just need more customers, and Btrfs is still on the road to be a manhood. Ceph Introduction (Led by Li Wang) This a hot topic.  Li gave us a nice introduction about the design as well as their current works. Actually, Ceph client has been included in Linux kernel since 2.6.34 and supported by Openstack since Folsom but it seems that it has not yet been widely deployment in production environment. Their major work is focus on the inline data support to separate the metadata and data storage, reduce the file access time, i.e, a file access need communication twice, fetch the metadata from MDS and then get data from OSD, and also, the small file access is limited by the network latency. The solution is, for the small files they would like to store the data at metadata so that when accessing a small file, the metadata server can push both metadata and data to the client at the same time. In this way, they can reduce the overhead of calculating the data offset and save the communication to OSD. For this feature, they have only run some small scale testing but really saw noticeable improvements. Test environment: Intel 2 CPU 12 Core, 64GB RAM, Ubuntu 12.04, Ceph 0.56.6 with 200GB SATA disk, 15 OSD, 1 MDS, 1 MON. The sequence read performance for 1K size files improved about 50%. I have asked Li and Zheng Yan (the core developer of Ceph, who also worked on Btrfs) whether Ceph is really stable and can be deployed at production environment for large scale PB level storage, but they can not give a positive answer, looks Ceph even does not spread over Dreamhost (subject to confirmation). From Li, they only deployed Ceph for a small scale storage(32 nodes) although they'd like to try 6000 nodes in the future. Improve Linux swap for Flash storage (led by Shaohua Li) Because of high density, low power and low price, flash storage (SSD) is a good candidate to partially replace DRAM. A quick answer for this is using SSD as swap. But Linux swap is designed for slow hard disk storage, so there are a lot of challenges to efficiently use SSD for swap. SWAPOUT swap_map scan swap_map is the in-memory data structure to track swap disk usage, but it is a slow linear scan. It will become a bottleneck while finding many adjacent pages in the use of SSD. Shaohua Li have changed it to a cluster(128K) list, resulting in O(1) algorithm. However, this apporoach needs restrictive cluster alignment and only enabled for SSD. IO pattern In most cases, the swap io is in interleaved pattern because of mutiple reclaimers or a free cluster is shared by all reclaimers. Even though block layer can merge interleaved IO to some extent, but we cannot count on it completely. Hence the per-cpu cluster is added base on the previous change, it can help reclaimer do sequential IO and the block layer will be easier to merge IO. TLB flush: If we're reclaiming one active page, we should first move the page from active lru list to inactive lru list, and then reclaim the page from inactive lru to swap it out. During the process, we need to clear PTE twice: first is 'A'(ACCESS) bit, second is 'P'(PRESENT) bit. Processors need to send lots of ipi which make the TLB flush really expensive. Some works have been done to improve this, including rework smp_call_functiom_many() or remove the first TLB flush in x86, but there still have some arguments here and only parts of works have been pushed to mainline. SWAPIN: Page fault does iodepth=1 sync io, but it's a little waste if only issue a page size's IO. The obvious solution is doing swap readahead. But the current in-kernel swap readahead is arbitary(always 8 pages), and it always doesn't perform well for both random and sequential access workload. Shaohua introduced a new flag for madvise(MADV_WILLNEED) to do swap prefetch, so the changes happen in userspace API and leave the in-kernel readahead unchanged(but I think some improvement can also be done here). SWAP discard As we know, discard is important for SSD write throughout, but the current swap discard implementation is synchronous. He changed it to async discard which allow discard and write run in the same time. Meanwhile, the unit of discard is also optimized to cluster. Misc: lock contention For many concurrent swapout and swapin , the lock contention such as anon_vma or swap_lock is high, so he changed the swap_lock to a per-swap lock. But there still have some lock contention in very high speed SSD because of swapcache address_space lock. Zproject (led by Bob Liu) Bob gave us a very nice introduction about the current memory compression status. Now there are 3 projects(zswap/zram/zcache) which all aim at smooth swap IO storm and promote performance, but they all have their own pros and cons. ZSWAP It is implemented based on frontswap API and it uses a dynamic allocater named Zbud to allocate free pages. Zbud means pairs of zpages are "buddied" and it can only store at most two compressed pages in one page frame, so the max compress ratio is 50%. Each page frame is lru-linked and can do shink in memory pressure. If the compressed memory pool reach its limitation, shink or reclaim happens. It decompress the page frame into two new allocated pages and then write them to real swap device, but it can fail when allocating the two pages. ZRAM Acts as a compressed ramdisk and used as swap device, and it use zsmalloc as its allocator which has high density but may have fragmentation issues. Besides, page reclaim is hard since it will need more pages to uncompress and free just one page. ZRAM is preferred by embedded system which may not have any real swap device. Now both ZRAM and ZSWAP are in driver/staging tree, and in the mm community there are some disscussions of merging ZRAM into ZSWAP or viceversa, but no agreement yet. ZCACHE Handles file page compression but it is removed out of staging recently. From industry (led by Tang Jie, LSI) An LSI engineer introduced several new produces to us. The first is raid5/6 cards that it use full stripe writes to improve performance. The 2nd one he introduced is SandForce flash controller, who can understand data file types (data entropy) to reduce write amplification (WA) for nearly all writes. It's called DuraWrite and typical WA is 0.5. What's more, if enable its Dynamic Logical Capacity function module, the controller can do data compression which is transparent to upper layer. LSI testing shows that with this virtual capacity enables 1x TB drive can support up to 2x TB capacity, but the application must monitor free flash space to maintain optimal performance and to guard against free flash space exhaustion. He said the most useful application is for datebase. Another thing I think it's worth to mention is that a NV-DRAM memory in NMR/Raptor which is directly exposed to host system. Applications can directly access the NV-DRAM via a memory address - using standard system call mmap(). He said that it is very useful for database logging now. This kind of NVM produces are beginning to appear in recent years, and it is said that Samsung is building a research center in China for related produces. IMHO, NVM will bring an effect to current os layer especially on file system, e.g. its journaling may need to redesign to fully utilize these nonvolatile memory. OCFS2 (led by Canquan Shen) Without a doubt, HuaWei is the biggest contributor to OCFS2 in the past two years. They have posted 46 upstream patches and 39 patches have been merged. Their current project is based on 32/64 nodes cluster, but they also tried 128 nodes at the experimental stage. The major work they are working is to support ATS (atomic test and set), it can be works with DLM at the same time. Looks this idea is inspired by the vmware VMFS locking, i.e, http://blogs.vmware.com/vsphere/2012/05/vmfs-locking-uncovered.html CLK - 18th October 2013 Improving Linux Development with Better Tools (Andi Kleen) This talk focused on how to find/solve bugs along with the Linux complexity growing. Generally, we can do this with the following kind of tools: Static code checkers tools. e.g, sparse, smatch, coccinelle, clang checker, checkpatch, gcc -W/LTO, stanse. This can help check a lot of things, simple mistakes, complex problems, but the challenges are: some are very slow, false positives, may need a concentrated effort to get false positives down. Especially, no static checker I found can follow indirect calls (“OO in C”, common in kernel): struct foo_ops { int (*do_foo)(struct foo *obj); } foo->do_foo(foo); Dynamic runtime checkers, e.g, thread checkers, kmemcheck, lockdep. Ideally all kernel code would come with a test suite, then someone could run all the dynamic checkers. Fuzzers/test suites. e.g, Trinity is a great tool, it finds many bugs, but needs manual model for each syscall. Modern fuzzers around using automatic feedback, but notfor kernel yet: http://taviso.decsystem.org/making_software_dumber.pdf Debuggers/Tracers to understand code, e.g, ftrace, can dump on events/oops/custom triggers, but still too much overhead in many cases to run always during debug. Tools to read/understand source, e.g, grep/cscope work great for many cases, but do not understand indirect pointers (OO in C model used in kernel), give us all “do_foo” instances: struct foo_ops { int (*do_foo)(struct foo *obj); } = { .do_foo = my_foo }; foo>do_foo(foo); That would be great to have a cscope like tool that understands this based on types/initializers XFS: The High Performance Enterprise File System (Jeff Liu) [slides] I gave a talk for introducing the disk layout, unique features, as well as the recent changes.   The slides include some charts to reflect the performances between XFS/Btrfs/Ext4 for small files. About a dozen users raised their hands when I asking who has experienced with XFS. I remembered that when I asked the same question in LinuxCon/Japan, only 3 people raised their hands, but they are Chris Mason, Ric Wheeler, and another attendee. The attendee questions were mainly focused on stability, and comparison with other file systems. Linux Containers (Feng Gao) The speaker introduced us that the purpose for those kind of namespaces, include mount/UTS/IPC/Network/Pid/User, as well as the system API/ABI. For the userspace tools, He mainly focus on the Libvirt LXC rather than us(LXC). Libvirt LXC is another userspace container management tool, implemented as one type of libvirt driver, it can manage containers, create namespace, create private filesystem layout for container, Create devices for container and setup resources controller via cgroup. In this talk, Feng also mentioned another two possible new namespaces in the future, the 1st is the audit, but not sure if it should be assigned to user namespace or not. Another is about syslog, but the question is do we really need it? In-memory Compression (Bob Liu) Same as CLSF, a nice introduction that I have already mentioned above. Misc There were some other talks related to ACPI based memory hotplug, smart wake-affinity in scheduler etc., but my head is not big enough to record all those things. -- Jeff Liu

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  • Auto blocking attacking IP address

    - by dong
    This is to share my PowerShell code online. I original asked this question on MSDN forum (or TechNet?) here: http://social.technet.microsoft.com/Forums/en-US/winserversecurity/thread/f950686e-e3f8-4cf2-b8ec-2685c1ed7a77 In short, this is trying to find attacking IP address then add it into Firewall block rule. So I suppose: 1, You are running a Windows Server 2008 facing the Internet. 2, You need to have some port open for service, e.g. TCP 21 for FTP; TCP 3389 for Remote Desktop. You can see in my code I’m only dealing with these two since that’s what I opened. You can add further port number if you like, but the way to process might be different with these two. 3, I strongly suggest you use STRONG password and follow all security best practices, this ps1 code is NOT for adding security to your server, but reduce the nuisance from brute force attack, and make sys admin’s life easier: i.e. your FTP log won’t hold megabytes of nonsense, your Windows system log will not roll back and only can tell you what happened last month. 4, You are comfortable with setting up Windows Firewall rules, in my code, my rule has a name of “MY BLACKLIST”, you need to setup a similar one, and set it to BLOCK everything. 5, My rule is dangerous because it has the risk to block myself out as well. I do have a backup plan i.e. the DELL DRAC5 so that if that happens, I still can remote console to my server and reset the firewall. 6, By no means the code is perfect, the coding style, the use of PowerShell skills, the hard coded part, all can be improved, it’s just that it’s good enough for me already. It has been running on my server for more than 7 MONTHS. 7, Current code still has problem, I didn’t solve it yet, further on this point after the code. :)    #Dong Xie, March 2012  #my simple code to monitor attack and deal with it  #Windows Server 2008 Logon Type  #8: NetworkCleartext, i.e. FTP  #10: RemoteInteractive, i.e. RDP    $tick = 0;  "Start to run at: " + (get-date);    $regex1 = [regex] "192\.168\.100\.(?:101|102):3389\s+(\d+\.\d+\.\d+\.\d+)";  $regex2 = [regex] "Source Network Address:\t(\d+\.\d+\.\d+\.\d+)";    while($True) {   $blacklist = @();     "Running... (tick:" + $tick + ")"; $tick+=1;    #Port 3389  $a = @()  netstat -no | Select-String ":3389" | ? { $m = $regex1.Match($_); `    $ip = $m.Groups[1].Value; if ($m.Success -and $ip -ne "10.0.0.1") {$a = $a + $ip;} }  if ($a.count -gt 0) {    $ips = get-eventlog Security -Newest 1000 | Where-Object {$_.EventID -eq 4625 -and $_.Message -match "Logon Type:\s+10"} | foreach { `      $m = $regex2.Match($_.Message); $ip = $m.Groups[1].Value; $ip; } | Sort-Object | Tee-Object -Variable list | Get-Unique    foreach ($ip in $a) { if ($ips -contains $ip) {      if (-not ($blacklist -contains $ip)) {        $attack_count = ($list | Select-String $ip -SimpleMatch | Measure-Object).count;        "Found attacking IP on 3389: " + $ip + ", with count: " + $attack_count;        if ($attack_count -ge 20) {$blacklist = $blacklist + $ip;}      }      }    }  }      #FTP  $now = (Get-Date).AddMinutes(-5); #check only last 5 mins.     #Get-EventLog has built-in switch for EventID, Message, Time, etc. but using any of these it will be VERY slow.  $count = (Get-EventLog Security -Newest 1000 | Where-Object {$_.EventID -eq 4625 -and $_.Message -match "Logon Type:\s+8" -and `              $_.TimeGenerated.CompareTo($now) -gt 0} | Measure-Object).count;  if ($count -gt 50) #threshold  {     $ips = @();     $ips1 = dir "C:\inetpub\logs\LogFiles\FPTSVC2" | Sort-Object -Property LastWriteTime -Descending `       | select -First 1 | gc | select -Last 200 | where {$_ -match "An\+error\+occured\+during\+the\+authentication\+process."} `        | Select-String -Pattern "(\d+\.\d+\.\d+\.\d+)" | select -ExpandProperty Matches | select -ExpandProperty value | Group-Object `        | where {$_.Count -ge 10} | select -ExpandProperty Name;       $ips2 = dir "C:\inetpub\logs\LogFiles\FTPSVC3" | Sort-Object -Property LastWriteTime -Descending `       | select -First 1 | gc | select -Last 200 | where {$_ -match "An\+error\+occured\+during\+the\+authentication\+process."} `        | Select-String -Pattern "(\d+\.\d+\.\d+\.\d+)" | select -ExpandProperty Matches | select -ExpandProperty value | Group-Object `        | where {$_.Count -ge 10} | select -ExpandProperty Name;     $ips += $ips1; $ips += $ips2; $ips = $ips | where {$_ -ne "10.0.0.1"} | Sort-Object | Get-Unique;         foreach ($ip in $ips) {       if (-not ($blacklist -contains $ip)) {        "Found attacking IP on FTP: " + $ip;        $blacklist = $blacklist + $ip;       }     }  }        #Firewall change <# $current = (netsh advfirewall firewall show rule name="MY BLACKLIST" | where {$_ -match "RemoteIP"}).replace("RemoteIP:", "").replace(" ","").replace("/255.255.255.255",""); #inside $current there is no \r or \n need remove. foreach ($ip in $blacklist) { if (-not ($current -match $ip) -and -not ($ip -like "10.0.0.*")) {"Adding this IP into firewall blocklist: " + $ip; $c= 'netsh advfirewall firewall set rule name="MY BLACKLIST" new RemoteIP="{0},{1}"' -f $ip, $current; Invoke-Expression $c; } } #>    foreach ($ip in $blacklist) {    $fw=New-object –comObject HNetCfg.FwPolicy2; # http://blogs.technet.com/b/jamesone/archive/2009/02/18/how-to-manage-the-windows-firewall-settings-with-powershell.aspx    $myrule = $fw.Rules | where {$_.Name -eq "MY BLACKLIST"} | select -First 1; # Potential bug here?    if (-not ($myrule.RemoteAddresses -match $ip) -and -not ($ip -like "10.0.0.*"))      {"Adding this IP into firewall blocklist: " + $ip;         $myrule.RemoteAddresses+=(","+$ip);      }  }    Wait-Event -Timeout 30 #pause 30 secs    } # end of top while loop.   Further points: 1, I suppose the server is listening on port 3389 on server IP: 192.168.100.101 and 192.168.100.102, you need to replace that with your real IP. 2, I suppose you are Remote Desktop to this server from a workstation with IP: 10.0.0.1. Please replace as well. 3, The threshold for 3389 attack is 20, you don’t want to block yourself just because you typed your password wrong 3 times, you can change this threshold by your own reasoning. 4, FTP is checking the log for attack only to the last 5 mins, you can change that as well. 5, I suppose the server is serving FTP on both IP address and their LOG path are C:\inetpub\logs\LogFiles\FPTSVC2 and C:\inetpub\logs\LogFiles\FPTSVC3. Change accordingly. 6, FTP checking code is only asking for the last 200 lines of log, and the threshold is 10, change as you wish. 7, the code runs in a loop, you can set the loop time at the last line. To run this code, copy and paste to your editor, finish all the editing, get it to your server, and open an CMD window, then type powershell.exe –file your_powershell_file_name.ps1, it will start running, you can Ctrl-C to break it. This is what you see when it’s running: This is when it detected attack and adding the firewall rule: Regarding the design of the code: 1, There are many ways you can detect the attack, but to add an IP into a block rule is no small thing, you need to think hard before doing it, reason for that may include: You don’t want block yourself; and not blocking your customer/user, i.e. the good guy. 2, Thus for each service/port, I double check. For 3389, first it needs to show in netstat.exe, then the Event log; for FTP, first check the Event log, then the FTP log files. 3, At three places I need to make sure I’m not adding myself into the block rule. –ne with single IP, –like with subnet.   Now the final bit: 1, The code will stop working after a while (depends on how busy you are attacked, could be weeks, months, or days?!) It will throw Red error message in CMD, don’t Panic, it does no harm, but it also no longer blocking new attack. THE REASON is not confirmed with MS people: the COM object to manage firewall, you can only give it a list of IP addresses to the length of around 32KB I think, once it reaches the limit, you get the error message. 2, This is in fact my second solution to use the COM object, the first solution is still in the comment block for your reference, which is using netsh, that fails because being run from CMD, you can only throw it a list of IP to 8KB. 3, I haven’t worked the workaround yet, some ideas include: wrap that RemoteAddresses setting line with error checking and once it reaches the limit, use the newly detected IP to be the list, not appending to it. This basically reset your block rule to ground zero and lose the previous bad IPs. This does no harm as it sounds, because given a certain period has passed, any these bad IPs still not repent and continue the attack to you, it only got 30 seconds or 20 guesses of your password before you block it again. And there is the benefit that the bad IP may turn back to the good hands again, and you are not blocking a potential customer or your CEO’s home pc because once upon a time, it’s a zombie. Thus the ZEN of blocking: never block any IP for too long. 4, But if you insist to block the ugly forever, my other ideas include: You call MS support, ask them how can we set an arbitrary length of IP addresses in a rule; at least from my experiences at the Forum, they don’t know and they don’t care, because they think the dynamic blocking should be done by some expensive hardware. Or, from programming perspective, you can create a new rule once the old is full, then you’ll have MY BLACKLIST1, MY  BLACKLIST2, MY BLACKLIST3, … etc. Once in a while you can compile them together and start a business to sell your blacklist on the market! Enjoy the code! p.s. (PowerShell is REALLY REALLY GREAT!)

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  • CodePlex Daily Summary for Sunday, June 03, 2012

    CodePlex Daily Summary for Sunday, June 03, 2012Popular ReleasesLiveChat Starter Kit: LCSK v1.5.2: New features: Visitor location (City - Country) from geo-location Pass configuration via javascript for the chat box New visitor identification (no more using the IP address as visitor identification) To update from 1.5.1 Run the /src/1.5.2-sql-updates.txt SQL script to update your database tables. If you have it installed via NuGet, simply update your package and the file will be included so you can run the update script. New installation The easiest way to add LCSK to your app is by...Prime Factorization: Prime Factorization V2: Download the installation package and run it, to install prime factorization on your computer.DNN Content Localization Tools: CLTools v0.4 (Beta4): 3th Beta release for DNN 6.1 and obove Bug corrections : - Copy module work againNTemplates: NTemplates full source code and examples: This release includes the following changes: - NTemplates code. More enhacements and bug fixing. Nested scans seems to be working ok now. New event: ScanStart. Very usuful for calculating totals (see the example) - Examples. 2 new examples on nested scans. One of them very simple I did just for debugging. The other one is a report of invoices grouped by vendor, including totals calculations. Planned Roadmap: - Work on fixing performance bottlenecek: Try to compile the expression...ZXMAK2: Version 2.6.2.3: - add support for ZIP files created on UNIX system; - improve WAV support (fixed PCM24, FLOAT32; added PCM32, FLOAT64); - fix drag-n-drop on modal dialogs; - tape AutoPlay feature (thanks to Woody for algorithm).Net Code Samples: Full WCF Duplex Service Example: Full WCF Duplex Service ExampleKendo UI ASP.NET Sample Applications: Sample Applications (2012-06-01): Sample application(s) demonstrating the use of Kendo UI in ASP.NET applications.Better Explorer: Better Explorer Beta 1: Finally, the first Beta is here! There were a lot of changes, including: Translations into 10 different languages (the translations are not complete and will be updated soon) Conditional Select new tools for managing archives Folder Tools tab new search bar and Search Tab new image editing tools update function many bug fixes, stability fixes, and memory leak fixes other new features as well! Please check it out and if there are any problems, let us know. :) Also, do not forge...myManga: myManga v1.0.0.3: Will include MangaPanda as a default option. ChangeLog Updating from Previous Version: Extract contents of Release - myManga v1.0.0.3.zip to previous version's folder. Replaces: myManga.exe BakaBox.dll CoreMangaClasses.dll Manga.dll Plugins/MangaReader.manga.dll Plugins/MangaFox.manga.dll Plugins/MangaHere.manga.dll Plugins/MangaPanda.manga.dllPlayer Framework by Microsoft: Player Framework for Windows 8 Metro (Preview 3): Player Framework for HTML/JavaScript and XAML/C# Metro Style Applications. Additional DownloadsIIS Smooth Streaming Client SDK for Windows 8 Microsoft PlayReady Client SDK for Metro Style Apps Release notes:Support for Windows 8 Release Preview (released 5/31/12) Advertising support (VAST, MAST, VPAID, & clips) Miscellaneous improvements and bug fixesMicrosoft Ajax Minifier: Microsoft Ajax Minifier 4.54: Fix for issue #18161: pretty-printing CSS @media rule throws an exception due to mismatched Indent/Unindent pair.Silverlight Toolkit: Silverlight 5 Toolkit Source - May 2012: Source code for December 2011 Silverlight 5 Toolkit release.Windows 8 Metro RSS Reader: RSS Reader release 6: Changed background and foreground colors Used VariableSizeGrid layout to wrap blog posts with images Sort items with Images first, text-only last Enabled Caching to improve navigation between framesJson.NET: Json.NET 4.5 Release 6: New feature - Added IgnoreDataMemberAttribute support New feature - Added GetResolvedPropertyName to DefaultContractResolver New feature - Added CheckAdditionalContent to JsonSerializer Change - Metro build now always uses late bound reflection Change - JsonTextReader no longer returns no content after consecutive underlying content read failures Fix - Fixed bad JSON in an array with error handling creating an infinite loop Fix - Fixed deserializing objects with a non-default cons...DotNetNuke® Community Edition CMS: 06.02.00: Major Highlights Fixed issue in the Site Settings when single quotes were being treated as escape characters Fixed issue loading the Mobile Premium Data after upgrading from CE to PE Fixed errors logged when updating folder provider settings Fixed the order of the mobile device capabilities in the Site Redirection Management UI The User Profile page was completely rebuilt. We needed User Profiles to have multiple child pages. This would allow for the most flexibility by still f...????: ????2.0.1: 1、?????。WiX Toolset: WiX v3.6 RC: WiX v3.6 RC (3.6.2928.0) provides feature complete Burn with VS11 support. For more information see Rob's blog post about the release: http://robmensching.com/blog/posts/2012/5/28/WiX-v3.6-Release-Candidate-availableJavascript .NET: Javascript .NET v0.7: SetParameter() reverts to its old behaviour of allowing JavaScript code to add new properties to wrapped C# objects. The behavior added briefly in 0.6 (throws an exception) can be had via the new SetParameterOptions.RejectUnknownProperties. TerminateExecution now uses its isolate to terminate the correct context automatically. Added support for converting all C# integral types, decimal and enums to JavaScript numbers. (Previously only the common types were handled properly.) Bug fixe...Phalanger - The PHP Language Compiler for the .NET Framework: 3.0 (May 2012): Fixes: unserialize() of negative float numbers fix pcre possesive quantifiers and character class containing ()[] array deserilization when the array contains a reference to ISerializable parsing lambda function fix round() reimplemented as it is in PHP to avoid .NET rounding errors filesize bypass for FileInfo.Length bug in Mono New features: Time zones reimplemented, uses Windows/Linux databaseSharePoint Euro 2012 - UEFA European Football Predictor: havivi.euro2012.wsp (1.1): New fetures:Admin enable / disable match Hide/Show Euro 2012 SharePoint lists (3 lists) Installing SharePoint Euro 2012 PredictorSharePoint Euro 2012 Predictor has been developed as a SharePoint Sandbox solution to support SharePoint Online (Office 365) Download the solution havivi.euro2012.wsp from the download page: Downloads Upload this solution to your Site Collection via the solutions area. Click on Activate to make the web parts in the solution available for use in the Site C...New ProjectsAFS.PhonePusherConnectorVX: pusher for phone vxApache: this is the Apache project.Apple: this is the Apple project.CUARTOAZZJL: HURRA!!Designing Windows 8 Applications with C# and XAML: This project hosts the source code used in the example projects for the book, Designing Windows 8 Metro Applications with C# and XAML.Easy Internet: CyberWeb ist ein einfacher Webbrowser für PC Neulinge. Ideal für Leute, die noch keine PC-Erfahrung haben.Easy Outlook Backup: Beschreibung: Easy Outlook Backup ist ein Programm das alle Daten von Outlook sichert. Ideal für Leute, die noch keine PC-Erfahrung haben. Easy Realtime Start: Beschreibung: Easy Realtime Start ist ein Programm das einen Prozess in höchster Priorität startet. Und das ganz bequem Per drag & drop. Ideal für Leute, die aufwendige Programme starten müssen. (zB.: “Blender” Free 3D Designer)eStock: eStock ist ein Verwaltungstool für Elektroniker um Bauteile im "Lager" sowie Projekte zu verwalten. Es bietet eine Möglichkeit festzulegen, um welche Art von Bauteil es sich handelt und wo sich dieses im Lager bzw. Regal befindet. Die Projektverwaltung ermöglicht es, Bauteile einem Projekt hinzuzufügen und eine Bestellliste / Einkaufsliste von Bauteilen, die nicht mehr im Lager vorhanden sind, zu erstellen. FuTTY: FireEgl's PuTTY -- FuTTY! FuTTY is a fork of PuTTY and PuTTYTray.GeometryWorld: To Do...Google: this is the Google project.Google Advance Search: An easy way to create documents search at Google and read your emails and Much moregoogle maps viewer for dynamics crm 2011: Easy google maps viewer for dynamics CRM 2011GPS Status - (GPS tool für GPS-Dongles und Mäuse) - GPS-Empfänger: Mein Programm verbindet sich mit dem externen GPS über einen Com-Port und bietet verschiedene Tools.Harmony Text Editor: Harmony is a ridiculously simple text editor for code and poetry.Hi! Football: .Goal / Objective -> To help friends gather for enjoying watching football together. .How it works -> To basically choose your favorite team, choose one of the matches fetched for his team, our app will generate a list of popular restraunts, cafes where he can watch the chosen match, the user can select one of the generated locations around his area, and create an event inviting his friends to join him and he can also join other friends' events.Java: this is the Java project.LevelUp Serializer: LevelUp Serializer is a small and simple serialize library.It can help developer to serialize and deserialize data more convenient. Feature: - Ease of use - Supports almost all serializer, like Binary、Xml、Soap、Json、DataContract. - Support serialize to file、serialize to stream、deserialize from file、deserialize from stream. - Support Xml encryption. - Support accelerated through the XML the serialization assemble.LFormatConvert: ????Linux???????????????????????,??ffmpeg????Machine QA Manager: Machine QA Manager is intended to save and help trend results from radiation therapy equipment testing. The program will be made as generic as possible from a initial setup to enable it's use for other types of routine testing activities (for example factory equipment) but preconfigured templates for radiation therapy will be supplied for the convenience of people working in that domain.maven-asbuild-plugin: maven-asbuild-plugin incorporates the adobe flash/flex based artifacts like swc or swf into the maven methology.Midnight Peach - C# framework generator for LINQ: C# framework generator for LINQMiku???????: ????????,????????!?????????????,??????????。?????????????????!MIKU????????????,??!????????????、????。 This program used to detect music beat.You can listen to music while press button,and it can display the BPM of the song.Miku will wave to you.MyTestingStudy: my personal testing studyNameless Sprite Editor: Nameless Sprite Editor is a tool used to thoroughly edit the graphics in ALL Game Boy Advance games. [ UNDER CONSTRUCTION ]NeoModulus Business Rules Builder: A windows form application that allows non-programmers to build strict definitions of a business domain. Once the definition is complete the program will build out object oriented C# files and a .net DLL. My test business domain is the open SRD, basically Dungeons and Dragons 3.5 edition.NodeJs: this is the NodeJs projectNoSQL: this is the Nosql project.OmniKassa for NopCommerce: OmniKassa payment module plugin for nopCommerceOn-Line Therapy: testOpen School: This project is about to create an open platform for all the academic institutions, so that they can manage all of their work. Our efforts will be for every kind of institution who are currently struggling with different kind of systems in place which are not collaborating with each other. This project will provide a common platform to all these kind of systems and provide them a better solution which actually works. Oracle: this is the Oracle project.Orchard Web Services: RESTful web services to expose interaction with Orchard content management.Personal Social Network using asp.net mvc and mongodb: FirstRooster is a network platform that let user create their own social network of interest to connect and share with like minded people anywhere.peshop: E-Commerce application , separated by DAl,BLL and Presentation layersPHP: this is the PHP project.Prime Factorization: Factoring trinomials using the ac method can be made easier through the use of Prime Factorization. Prime Factorization is a program that can assist you in the factoring of numbers in Algebra, namely trinomials using the AC Method. It can also find all the factors of any number.PromedioNotas: El programa trata de promediar 3 nostas y mostrar y si pasaba de año o no por medio de un mensajeProyecto Tarea: Este proyecto esta hecho con el objetivo de aprender sobre TFSProyectotarea1: Sotfware de terminal aéreo de Guayaquil, donde se encuentran el nombre de las aerolíneas y las rutas de vuelo a nivel nacional.Python: this is the Python project.Ruby: this is the Ruby project.tedplay: tedplay is your media player of choice for playing Commodore 264 music format files similar to SIDplay. It is basically a stripped down Commodore plus/4 emulator without video output and peripherals based on the SDL build of the Commodore 264 family emulator YAPE. tedplay is released under version 2 of the GNU Generic Public License and can be built for both Windows and Unix or actually any platform that has a C++ compiler and SDL support.test1: This is a test projectwin-x264: A port of the x264-codebase into a VisualStudio-project. Compilation requires Intel-compiler and Yasm.XDA ROM Hub: Xperia 2011 line toolkit.znvicente_cuartoc: Poyecto Vicente Eduardo Zambrano Navarrete??Win7?????: ??????? *.theme ???????(??,??,??,???)。????VSB???*.msstyles??,????????,????????????????????????!????????????,?????????????。???,????????! ?????????,?????????,????????,??????!?????????????,?????????????????,?????????,???Aero??,??????~?????????????!??,?????????theme??,?????????,??????,????,??????。 This program used to create .theme file and the relevant documents (wallpaper, pointer, ICONS, sounds, etc.). As long as you use VSB ready . msstyles files, chosen the icon wallpaper, etc, an...

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  • Partitioned Repository for WebCenter Content using Oracle Database 11g

    - by Adao Junior
    One of the biggest challenges for content management solutions is related to the storage management due the high volumes of the unstoppable growing of information. Even if you have storage appliances and a lot of terabytes, thinks like backup, compression, deduplication, storage relocation, encryption, availability could be a nightmare. One standard option that you have with the Oracle WebCenter Content is to store data to the database. And the Oracle Database allows you leverage features like compression, deduplication, encryption and seamless backup. But with a huge volume, the challenge is passed to the DBA to keep the WebCenter Content Database up and running. One solution is the use of DB partitions for your content repository, but what are the implications of this? Can I fit this with my business requirements? Well, yes. It’s up to you how you will manage that, you just need a good plan. During you “storage brainstorm plan” take in your mind what you need, such as storage petabytes of documents? You need everything on-line? There’s a way to logically separate the “good content” from the “legacy content”? The first thing that comes to my mind is to use the creation date of the document, but you need to remember that this document could receive a lot of revisions and maybe you can consider the revision creation date. Your plan can have also complex rules like per Document Type or per a custom metadata like department or an hybrid per date, per DocType and an specific virtual folder. Extrapolation the use, you can have your repository distributed in different servers, different disks, different disk types (Such as ssds, sas, sata, tape,…), separated accordingly your business requirements, separating the “hot” content from the legacy and easily matching your compliance requirements. If you think to use by revision, the simple way is to consider the dId, that is the sequential unique id for every content created using the WebCenter Content or the dLastModified that is the date field of the FileStorage table that contains the date of inclusion of the content to the DB Table using SecureFiles. Using the scenario of partitioned repository using an hierarchical separation by date, we will transform the FileStorage table in an partitioned table using  “Partition by Range” of the dLastModified column (You can use the dId or a join with other tables for other metadata such as dDocType, Security, etc…). The test scenario bellow covers: Previous existent data on the JDBC Storage to be migrated to the new partitioned JDBC Storage Partition by Date Automatically generation of new partitions based on a pre-defined interval (Available only with Oracle Database 11g+) Deduplication and Compression for legacy data Oracle WebCenter Content 11g PS5 (Could present some customizations that do not affect the test scenario) For the test case you need some data stored using JDBC Storage to be the “legacy” data. If you do not have done before, just create an Storage rule pointed to the JDBC Storage: Enable the metadata StorageRule in the UI and upload some documents using this rule. For this test case you can run using the schema owner or an dba user. We will use the schema owner TESTS_OCS. I can’t forgot to tell that this is just a test and you should do a proper backup of your environment. When you use the schema owner, you need some privileges, using the dba user grant the privileges needed: REM Grant privileges required for online redefinition. GRANT EXECUTE ON DBMS_REDEFINITION TO TESTS_OCS; GRANT ALTER ANY TABLE TO TESTS_OCS; GRANT DROP ANY TABLE TO TESTS_OCS; GRANT LOCK ANY TABLE TO TESTS_OCS; GRANT CREATE ANY TABLE TO TESTS_OCS; GRANT SELECT ANY TABLE TO TESTS_OCS; REM Privileges required to perform cloning of dependent objects. GRANT CREATE ANY TRIGGER TO TESTS_OCS; GRANT CREATE ANY INDEX TO TESTS_OCS; In our test scenario we will separate the content as Legacy, Day1, Day2, Day3 and Future. This last one will partitioned automatically using 3 tablespaces in a round robin mode. In a real scenario the partition rule could be per month, per year or any rule that you choose. Table spaces for the test scenario: CREATE TABLESPACE TESTS_OCS_PART_LEGACY DATAFILE 'tests_ocs_part_legacy.dat' SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_DAY1 DATAFILE 'tests_ocs_part_day1.dat' SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_DAY2 DATAFILE 'tests_ocs_part_day2.dat' SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_DAY3 DATAFILE 'tests_ocs_part_day3.dat' SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_ROUND_ROBIN_A 'tests_ocs_part_round_robin_a.dat' DATAFILE SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_ROUND_ROBIN_B 'tests_ocs_part_round_robin_b.dat' DATAFILE SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_ROUND_ROBIN_C 'tests_ocs_part_round_robin_c.dat' DATAFILE SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; Before start, gather optimizer statistics on the actual FileStorage table: EXEC DBMS_STATS.GATHER_TABLE_STATS(USER, 'FileStorage', cascade => TRUE); Now check if is possible execute the redefinition process: EXEC DBMS_REDEFINITION.CAN_REDEF_TABLE('TESTS_OCS', 'FileStorage',DBMS_REDEFINITION.CONS_USE_PK); If no errors messages, you are good to go. Create a Partitioned Interim FileStorage table. You need to create a new table with the partition information to act as an interim table: CREATE TABLE FILESTORAGE_Part ( DID NUMBER(*,0) NOT NULL ENABLE, DRENDITIONID VARCHAR2(30 CHAR) NOT NULL ENABLE, DLASTMODIFIED TIMESTAMP (6), DFILESIZE NUMBER(*,0), DISDELETED VARCHAR2(1 CHAR), BFILEDATA BLOB ) LOB (BFILEDATA) STORE AS SECUREFILE ( ENABLE STORAGE IN ROW NOCACHE LOGGING KEEP_DUPLICATES NOCOMPRESS ) PARTITION BY RANGE (DLASTMODIFIED) INTERVAL (NUMTODSINTERVAL(1,'DAY')) STORE IN (TESTS_OCS_PART_ROUND_ROBIN_A, TESTS_OCS_PART_ROUND_ROBIN_B, TESTS_OCS_PART_ROUND_ROBIN_C) ( PARTITION FILESTORAGE_PART_LEGACY VALUES LESS THAN (TO_DATE('05-APR-2012 12.00.00 AM', 'DD-MON-YYYY HH.MI.SS AM')) TABLESPACE TESTS_OCS_PART_LEGACY LOB (BFILEDATA) STORE AS SECUREFILE ( TABLESPACE TESTS_OCS_PART_LEGACY RETENTION NONE DEDUPLICATE COMPRESS HIGH ), PARTITION FILESTORAGE_PART_DAY1 VALUES LESS THAN (TO_DATE('06-APR-2012 07.25.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) TABLESPACE TESTS_OCS_PART_DAY1 LOB (BFILEDATA) STORE AS SECUREFILE ( TABLESPACE TESTS_OCS_PART_DAY1 RETENTION AUTO KEEP_DUPLICATES COMPRESS ), PARTITION FILESTORAGE_PART_DAY2 VALUES LESS THAN (TO_DATE('06-APR-2012 07.55.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) TABLESPACE TESTS_OCS_PART_DAY2 LOB (BFILEDATA) STORE AS SECUREFILE ( TABLESPACE TESTS_OCS_PART_DAY2 RETENTION AUTO KEEP_DUPLICATES NOCOMPRESS ), PARTITION FILESTORAGE_PART_DAY3 VALUES LESS THAN (TO_DATE('06-APR-2012 07.58.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) TABLESPACE TESTS_OCS_PART_DAY3 LOB (BFILEDATA) STORE AS SECUREFILE ( TABLESPACE TESTS_OCS_PART_DAY3 RETENTION AUTO KEEP_DUPLICATES NOCOMPRESS ) ); After the creation you should see your partitions defined. Note that only the fixed range partitions have been created, none of the interval partition have been created. Start the redefinition process: BEGIN DBMS_REDEFINITION.START_REDEF_TABLE( uname => 'TESTS_OCS' ,orig_table => 'FileStorage' ,int_table => 'FileStorage_PART' ,col_mapping => NULL ,options_flag => DBMS_REDEFINITION.CONS_USE_PK ); END; This operation can take some time to complete, depending how many contents that you have and on the size of the table. Using the DBA user you can check the progress with this command: SELECT * FROM v$sesstat WHERE sid = 1; Copy dependent objects: DECLARE redefinition_errors PLS_INTEGER := 0; BEGIN DBMS_REDEFINITION.COPY_TABLE_DEPENDENTS( uname => 'TESTS_OCS' ,orig_table => 'FileStorage' ,int_table => 'FileStorage_PART' ,copy_indexes => DBMS_REDEFINITION.CONS_ORIG_PARAMS ,copy_triggers => TRUE ,copy_constraints => TRUE ,copy_privileges => TRUE ,ignore_errors => TRUE ,num_errors => redefinition_errors ,copy_statistics => FALSE ,copy_mvlog => FALSE ); IF (redefinition_errors > 0) THEN DBMS_OUTPUT.PUT_LINE('>>> FileStorage to FileStorage_PART temp copy Errors: ' || TO_CHAR(redefinition_errors)); END IF; END; With the DBA user, verify that there's no errors: SELECT object_name, base_table_name, ddl_txt FROM DBA_REDEFINITION_ERRORS; *Note that will show 2 lines related to the constrains, this is expected. Synchronize the interim table FileStorage_PART: BEGIN DBMS_REDEFINITION.SYNC_INTERIM_TABLE( uname => 'TESTS_OCS', orig_table => 'FileStorage', int_table => 'FileStorage_PART'); END; Gather statistics on the new table: EXEC DBMS_STATS.GATHER_TABLE_STATS(USER, 'FileStorage_PART', cascade => TRUE); Complete the redefinition: BEGIN DBMS_REDEFINITION.FINISH_REDEF_TABLE( uname => 'TESTS_OCS', orig_table => 'FileStorage', int_table => 'FileStorage_PART'); END; During the execution the FileStorage table is locked in exclusive mode until finish the operation. After the last command the FileStorage table is partitioned. If you have contents out of the range partition, you should see the new partitions created automatically, not generating an error if you “forgot” to create all the future ranges. You will see something like: You now can drop the FileStorage_PART table: border-bottom-width: 1px; border-bottom-style: solid; text-align: left; border-left-color: silver; border-left-width: 1px; border-left-style: solid; padding-bottom: 4px; line-height: 12pt; background-color: #f4f4f4; margin-top: 20px; margin-right: 0px; margin-bottom: 10px; margin-left: 0px; padding-left: 4px; width: 97.5%; padding-right: 4px; font-family: 'Courier New', Courier, monospace; direction: ltr; max-height: 200px; font-size: 8pt; overflow-x: auto; overflow-y: auto; border-top-color: silver; border-top-width: 1px; border-top-style: solid; cursor: text; border-right-color: silver; border-right-width: 1px; border-right-style: solid; padding-top: 4px; " id="codeSnippetWrapper"> DROP TABLE FileStorage_PART PURGE; To check the FileStorage table is valid and is partitioned, use the command: SELECT num_rows,partitioned FROM user_tables WHERE table_name = 'FILESTORAGE'; You can list the contents of the FileStorage table in a specific partition, per example: SELECT * FROM FileStorage PARTITION (FILESTORAGE_PART_LEGACY) Some useful commands that you can use to check the partitions, note that you need to run using a DBA user: SELECT * FROM DBA_TAB_PARTITIONS WHERE table_name = 'FILESTORAGE';   SELECT * FROM DBA_TABLESPACES WHERE tablespace_name like 'TESTS_OCS%'; After the redefinition process complete you have a new FileStorage table storing all content that has the Storage rule pointed to the JDBC Storage and partitioned using the rule set during the creation of the temporary interim FileStorage_PART table. At this point you can test the WebCenter Content downloading the documents (Original and Renditions). Note that the content could be already in the cache area, take a look in the weblayout directory to see if a file with the same id is there, then click on the web rendition of your test file and see if have created the file and you can open, this means that is all working. The redefinition process can be repeated many times, this allow you test what the better layout, over and over again. Now some interesting maintenance actions related to the partitions: Make an tablespace read only. No issues viewing, the WebCenter Content do not alter the revisions When try to delete an content that is part of an read only tablespace, an error will occurs and the document will not be deleted The only way to prevent errors today is creating an custom component that checks the partitions and if you have an document in an “Read Only” repository, execute the deletion process of the metadata and mark the document to be deleted on the next db maintenance, like a new redefinition. Take an tablespace off-line for archiving purposes or any other reason. When you try open an document that is included in this tablespace will receive an error that was unable to retrieve the content, but the others online tablespaces are not affected. Same behavior when deleting documents. Again, an custom component is the solution. If you have an document “out of range”, the component can show an message that the repository for that document is offline. This can be extended to a option to the user to request to put online again. Moving some legacy content to an offline repository (table) using the Exchange option to move the content from one partition to a empty nonpartitioned table like FileStorage_LEGACY. Note that this option will remove the registers from the FileStorage and will not be able to open the stored content. You always need to keep in mind the indexes and constrains. An redefinition separating the original content (vault) from the renditions and separate by date ate the same time. This could be an option for DAM environments that want to have an special place for the renditions and put the original files in a storage with less performance. The process will be the same, you just need to change the script of the interim table to use composite partitioning. Will be something like: CREATE TABLE FILESTORAGE_RenditionPart ( DID NUMBER(*,0) NOT NULL ENABLE, DRENDITIONID VARCHAR2(30 CHAR) NOT NULL ENABLE, DLASTMODIFIED TIMESTAMP (6), DFILESIZE NUMBER(*,0), DISDELETED VARCHAR2(1 CHAR), BFILEDATA BLOB ) LOB (BFILEDATA) STORE AS SECUREFILE ( ENABLE STORAGE IN ROW NOCACHE LOGGING KEEP_DUPLICATES NOCOMPRESS ) PARTITION BY LIST (DRENDITIONID) SUBPARTITION BY RANGE (DLASTMODIFIED) ( PARTITION Vault VALUES ('primaryFile') ( SUBPARTITION FILESTORAGE_VAULT_LEGACY VALUES LESS THAN (TO_DATE('05-APR-2012 12.00.00 AM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_VAULT_DAY1 VALUES LESS THAN (TO_DATE('06-APR-2012 07.25.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_VAULT_DAY2 VALUES LESS THAN (TO_DATE('06-APR-2012 07.55.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_VAULT_DAY3 VALUES LESS THAN (TO_DATE('06-APR-2012 07.58.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_VAULT_FUTURE VALUES LESS THAN (MAXVALUE) ) ,PARTITION WebLayout VALUES ('webViewableFile') ( SUBPARTITION FILESTORAGE_WEBLAYOUT_LEGACY VALUES LESS THAN (TO_DATE('05-APR-2012 12.00.00 AM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_WEBLAYOUT_DAY1 VALUES LESS THAN (TO_DATE('06-APR-2012 07.25.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_WEBLAYOUT_DAY2 VALUES LESS THAN (TO_DATE('06-APR-2012 07.55.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_WEBLAYOUT_DAY3 VALUES LESS THAN (TO_DATE('06-APR-2012 07.58.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_WEBLAYOUT_FUTURE VALUES LESS THAN (MAXVALUE) ) ,PARTITION Special VALUES ('Special') ( SUBPARTITION FILESTORAGE_SPECIAL_LEGACY VALUES LESS THAN (TO_DATE('05-APR-2012 12.00.00 AM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_SPECIAL_DAY1 VALUES LESS THAN (TO_DATE('06-APR-2012 07.25.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_SPECIAL_DAY2 VALUES LESS THAN (TO_DATE('06-APR-2012 07.55.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_SPECIAL_DAY3 VALUES LESS THAN (TO_DATE('06-APR-2012 07.58.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_SPECIAL_FUTURE VALUES LESS THAN (MAXVALUE) ) )ENABLE ROW MOVEMENT; The next post related to partitioned repository will come with an sample component to handle the possible exceptions when you need to take off line an tablespace/partition or move to another place. Also, we can include some integration to the Retention Management and Records Management. Another subject related to partitioning is the ability to create an FileStore Provider pointed to a different database, raising the level of the distributed storage vs. performance. Let us know if this is important to you or you have an use case not listed, leave a comment. Cross-posted on the blog.ContentrA.com

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  • Plan Caching and Query Memory Part II (Hash Match) – When not to use stored procedure - Most common performance mistake SQL Server developers make.

    - by sqlworkshops
    SQL Server estimates Memory requirement at compile time, when stored procedure or other plan caching mechanisms like sp_executesql or prepared statement are used, the memory requirement is estimated based on first set of execution parameters. This is a common reason for spill over tempdb and hence poor performance. Common memory allocating queries are that perform Sort and do Hash Match operations like Hash Join or Hash Aggregation or Hash Union. This article covers Hash Match operations with examples. It is recommended to read Plan Caching and Query Memory Part I before this article which covers an introduction and Query memory for Sort. In most cases it is cheaper to pay for the compilation cost of dynamic queries than huge cost for spill over tempdb, unless memory requirement for a query does not change significantly based on predicates.   This article covers underestimation / overestimation of memory for Hash Match operation. Plan Caching and Query Memory Part I covers underestimation / overestimation for Sort. It is important to note that underestimation of memory for Sort and Hash Match operations lead to spill over tempdb and hence negatively impact performance. Overestimation of memory affects the memory needs of other concurrently executing queries. In addition, it is important to note, with Hash Match operations, overestimation of memory can actually lead to poor performance.   To read additional articles I wrote click here.   The best way to learn is to practice. To create the below tables and reproduce the behavior, join the mailing list by using this link: www.sqlworkshops.com/ml and I will send you the table creation script. Most of these concepts are also covered in our webcasts: www.sqlworkshops.com/webcasts  Let’s create a Customer’s State table that has 99% of customers in NY and the rest 1% in WA.Customers table used in Part I of this article is also used here.To observe Hash Warning, enable 'Hash Warning' in SQL Profiler under Events 'Errors and Warnings'. --Example provided by www.sqlworkshops.com drop table CustomersState go create table CustomersState (CustomerID int primary key, Address char(200), State char(2)) go insert into CustomersState (CustomerID, Address) select CustomerID, 'Address' from Customers update CustomersState set State = 'NY' where CustomerID % 100 != 1 update CustomersState set State = 'WA' where CustomerID % 100 = 1 go update statistics CustomersState with fullscan go   Let’s create a stored procedure that joins customers with CustomersState table with a predicate on State. --Example provided by www.sqlworkshops.com create proc CustomersByState @State char(2) as begin declare @CustomerID int select @CustomerID = e.CustomerID from Customers e inner join CustomersState es on (e.CustomerID = es.CustomerID) where es.State = @State option (maxdop 1) end go  Let’s execute the stored procedure first with parameter value ‘WA’ – which will select 1% of data. set statistics time on go --Example provided by www.sqlworkshops.com exec CustomersByState 'WA' goThe stored procedure took 294 ms to complete.  The stored procedure was granted 6704 KB based on 8000 rows being estimated.  The estimated number of rows, 8000 is similar to actual number of rows 8000 and hence the memory estimation should be ok.  There was no Hash Warning in SQL Profiler. To observe Hash Warning, enable 'Hash Warning' in SQL Profiler under Events 'Errors and Warnings'.   Now let’s execute the stored procedure with parameter value ‘NY’ – which will select 99% of data. -Example provided by www.sqlworkshops.com exec CustomersByState 'NY' go  The stored procedure took 2922 ms to complete.   The stored procedure was granted 6704 KB based on 8000 rows being estimated.    The estimated number of rows, 8000 is way different from the actual number of rows 792000 because the estimation is based on the first set of parameter value supplied to the stored procedure which is ‘WA’ in our case. This underestimation will lead to spill over tempdb, resulting in poor performance.   There was Hash Warning (Recursion) in SQL Profiler. To observe Hash Warning, enable 'Hash Warning' in SQL Profiler under Events 'Errors and Warnings'.   Let’s recompile the stored procedure and then let’s first execute the stored procedure with parameter value ‘NY’.  In a production instance it is not advisable to use sp_recompile instead one should use DBCC FREEPROCCACHE (plan_handle). This is due to locking issues involved with sp_recompile, refer to our webcasts, www.sqlworkshops.com/webcasts for further details.   exec sp_recompile CustomersByState go --Example provided by www.sqlworkshops.com exec CustomersByState 'NY' go  Now the stored procedure took only 1046 ms instead of 2922 ms.   The stored procedure was granted 146752 KB of memory. The estimated number of rows, 792000 is similar to actual number of rows of 792000. Better performance of this stored procedure execution is due to better estimation of memory and avoiding spill over tempdb.   There was no Hash Warning in SQL Profiler.   Now let’s execute the stored procedure with parameter value ‘WA’. --Example provided by www.sqlworkshops.com exec CustomersByState 'WA' go  The stored procedure took 351 ms to complete, higher than the previous execution time of 294 ms.    This stored procedure was granted more memory (146752 KB) than necessary (6704 KB) based on parameter value ‘NY’ for estimation (792000 rows) instead of parameter value ‘WA’ for estimation (8000 rows). This is because the estimation is based on the first set of parameter value supplied to the stored procedure which is ‘NY’ in this case. This overestimation leads to poor performance of this Hash Match operation, it might also affect the performance of other concurrently executing queries requiring memory and hence overestimation is not recommended.     The estimated number of rows, 792000 is much more than the actual number of rows of 8000.  Intermediate Summary: This issue can be avoided by not caching the plan for memory allocating queries. Other possibility is to use recompile hint or optimize for hint to allocate memory for predefined data range.Let’s recreate the stored procedure with recompile hint. --Example provided by www.sqlworkshops.com drop proc CustomersByState go create proc CustomersByState @State char(2) as begin declare @CustomerID int select @CustomerID = e.CustomerID from Customers e inner join CustomersState es on (e.CustomerID = es.CustomerID) where es.State = @State option (maxdop 1, recompile) end go  Let’s execute the stored procedure initially with parameter value ‘WA’ and then with parameter value ‘NY’. --Example provided by www.sqlworkshops.com exec CustomersByState 'WA' go exec CustomersByState 'NY' go  The stored procedure took 297 ms and 1102 ms in line with previous optimal execution times.   The stored procedure with parameter value ‘WA’ has good estimation like before.   Estimated number of rows of 8000 is similar to actual number of rows of 8000.   The stored procedure with parameter value ‘NY’ also has good estimation and memory grant like before because the stored procedure was recompiled with current set of parameter values.  Estimated number of rows of 792000 is similar to actual number of rows of 792000.    The compilation time and compilation CPU of 1 ms is not expensive in this case compared to the performance benefit.   There was no Hash Warning in SQL Profiler.   Let’s recreate the stored procedure with optimize for hint of ‘NY’. --Example provided by www.sqlworkshops.com drop proc CustomersByState go create proc CustomersByState @State char(2) as begin declare @CustomerID int select @CustomerID = e.CustomerID from Customers e inner join CustomersState es on (e.CustomerID = es.CustomerID) where es.State = @State option (maxdop 1, optimize for (@State = 'NY')) end go  Let’s execute the stored procedure initially with parameter value ‘WA’ and then with parameter value ‘NY’. --Example provided by www.sqlworkshops.com exec CustomersByState 'WA' go exec CustomersByState 'NY' go  The stored procedure took 353 ms with parameter value ‘WA’, this is much slower than the optimal execution time of 294 ms we observed previously. This is because of overestimation of memory. The stored procedure with parameter value ‘NY’ has optimal execution time like before.   The stored procedure with parameter value ‘WA’ has overestimation of rows because of optimize for hint value of ‘NY’.   Unlike before, more memory was estimated to this stored procedure based on optimize for hint value ‘NY’.    The stored procedure with parameter value ‘NY’ has good estimation because of optimize for hint value of ‘NY’. Estimated number of rows of 792000 is similar to actual number of rows of 792000.   Optimal amount memory was estimated to this stored procedure based on optimize for hint value ‘NY’.   There was no Hash Warning in SQL Profiler.   This article covers underestimation / overestimation of memory for Hash Match operation. Plan Caching and Query Memory Part I covers underestimation / overestimation for Sort. It is important to note that underestimation of memory for Sort and Hash Match operations lead to spill over tempdb and hence negatively impact performance. Overestimation of memory affects the memory needs of other concurrently executing queries. In addition, it is important to note, with Hash Match operations, overestimation of memory can actually lead to poor performance.   Summary: Cached plan might lead to underestimation or overestimation of memory because the memory is estimated based on first set of execution parameters. It is recommended not to cache the plan if the amount of memory required to execute the stored procedure has a wide range of possibilities. One can mitigate this by using recompile hint, but that will lead to compilation overhead. However, in most cases it might be ok to pay for compilation rather than spilling sort over tempdb which could be very expensive compared to compilation cost. The other possibility is to use optimize for hint, but in case one sorts more data than hinted by optimize for hint, this will still lead to spill. On the other side there is also the possibility of overestimation leading to unnecessary memory issues for other concurrently executing queries. In case of Hash Match operations, this overestimation of memory might lead to poor performance. When the values used in optimize for hint are archived from the database, the estimation will be wrong leading to worst performance, so one has to exercise caution before using optimize for hint, recompile hint is better in this case.   I explain these concepts with detailed examples in my webcasts (www.sqlworkshops.com/webcasts), I recommend you to watch them. The best way to learn is to practice. To create the above tables and reproduce the behavior, join the mailing list at www.sqlworkshops.com/ml and I will send you the relevant SQL Scripts.  Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   Disclaimer and copyright information:This article refers to organizations and products that may be the trademarks or registered trademarks of their various owners. Copyright of this article belongs to R Meyyappan / www.sqlworkshops.com. You may freely use the ideas and concepts discussed in this article with acknowledgement (www.sqlworkshops.com), but you may not claim any of it as your own work. This article is for informational purposes only; you use any of the suggestions given here entirely at your own risk.   R Meyyappan [email protected] LinkedIn: http://at.linkedin.com/in/rmeyyappan

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  • Understanding the value of Customer Experience & Loyalty for the Telecommunications Industry

    - by raul.goycoolea
    Worried by economic woes and market forces, especially in mature markets, communications service providers (CSPs) increasingly focus on improving customer experience. In fact, it seems difficult to find a major message by a C-level executive in the developed world that does not include something on "meeting and exceeding customers' needs". Frequently in customer satisfaction studies by prominent firms, CSPs fall short of the leadership demonstrated by other industries that take customer-centric approaches to their bottom-line strategies. Consider the following:Despite the continued impact of global economic crisis, in July 2010, Apple Computer posted record revenue and net quarterly profit. Those who attribute the results primarily to the iPhone 4 launch should note that Apple also shipped around 30% more Macintosh computers than the same period the previous year. Even sales of the iPod line increased by 8% in a highly commoditized, shrinking media player market. Finally, Apple began selling iPads during the quarter, with total sales of more than 3 million units. What does Apple have that the others lack? Well, some great products (and services) to be sure, but it also excels at customer service and support, marketing, and distribution, and has one of the strongest brands globally. Its products are useful, simple to use, easy to acquire and augment, high quality, and considered very cool. They also evoke such an emotional response from many of Apple's customers, which they turn up their noses at competitive products.In other words, Apple appears to have mastered virtually every aspect of customer experience and the resultant loyalty of its customer base - even in difficult financial times. Through that unwavering customer focus, Apple continues to drive its revenues and profits to new heights. Other customer loyalty leaders like Wal-Mart, Google, Toyota and Honda are also doing well by focusing on customer experience as an essential driver of profitability. Service providers should note this performance and ask themselves how they might leverage the same principles to increase their own profitability. After all, that is what customer experience and loyalty are all about: profitability.To successfully manage all the critical touch points of customer experience, CSPs must shun the one-size-fits-all approach. They can no longer afford to view customer service fundamentally as an act of altruism - which mentality dates back to the industry's civil service days, when CSPs were typically government organizations that were critical to economic development and public safety.As regulators and public officials have pushed, and continue to push, service providers to new heights of reliability - using incentives and punishments - most CSPs already have some of the fundamental building blocks of customer service in place. Yet despite that history and experience, service providers still lag other industries in providing what is seen as good customer service.As we observed in the TMF's 2009 Insights Research report, Customer Experience Management: Driving Loyalty & Profitability there has been resurgence in interest by CSPs. More and more of them have stated ambitions to catch up other industries, and they are realizing that good customer service is a powerful strategy for increasing business performance and profitability, not an act of good will.CSPs are recognizing the connection between customer experience and profitability, as demonstrated in many studies. For example, according to research by Bain & Company, a 5 percent improvement in customer retention rates can yield as much as a 75 percent increase in profits for companies across a range of industries.After decades of customer experience strategy formulation, Bain partner and business author, Frederick Reichheld, considers "would you recommend us to a friend?" as the ultimate question for a customer. How many times have you or your friends recommended an iPod, iPhone or a Mac? What do your children recommend to their peers? Their peers to them?There are certain steps service providers have to take to create more personalized relationships with their customers, as well as reduce churn and increase profitability, all while becoming leaner and more agile. First, they have to define customer experience, we define it as the result of the sum of observations, perceptions, thoughts and feelings arising from interactions and relationships between customers and their service provider(s). Virtually every customer touch point - whether directly or indirectly linked to service providers and their partners - contributes to customer perception, satisfaction, loyalty, and ultimately profitability. Gaining leadership in customer experience and satisfaction will not be a simple task, as it is affected by virtually every customer-facing aspect of the service provider, and in turn impacts the service provider deeply - especially on the all-important bottom line. The scope of issues affecting customer experience is complex and dynamic.With new services, devices and applications extending the basis of customer experience to domains beyond the direct control of the service provider, it is likely to increase in complexity and dynamism.Customer loyalty = increased profitsAs stated earlier, customer experience programs are not fundamentally altruistic exercises, but a strategic means of improving competitiveness and profitability in the short and long term. Loyalty is essential to deriving long term profits from customers.Some of the earliest loyalty programs date back to the 1930s, when packaged goods companies offered embedded coupons for rewards to buyers, and eventually retail chains began offering reward programs to frequent shoppers. These programs continued for decades but were leapfrogged in the 1980s by more aggressive programs from the airlines.This movement was led by American Airlines, which launched the first full-scale loyalty marketing program of the modern era with the AAdvantage frequent flyer scheme. It was the first to reward frequent fliers with notional air miles that could be accumulated and later redeemed for free travel. Figure 1: Opportunities example of Customer loyalty driven profitOther airlines and travel providers were quick to grasp the incredible value of providing customers with an incentive to use their company exclusively. Within a few years, dozens of travel industry companies launched similar initiatives and now loyalty programs are achieving near-ubiquity in many service industries, especially those in which it is difficult to differentiate offerings by product attributes.The belief is that increased profitability will result from customer retention efforts because:•    The cost of acquisition occurs only at the beginning of a relationship: the longer the relationship, the lower the amortized cost;•    Account maintenance costs decline as a percentage of total costs, or as a percentage of revenue, over the lifetime of the relationship;•    Long term customers tend to be less inclined to switch and less price sensitive which can result in stable unit sales volume and increases in dollar-sales volume;•    Long term customers may initiate word-of-mouth promotions and referrals, which cost the company nothing and arguably are the most effective form of advertising;•    Long-term customers are more likely to buy ancillary products and higher margin supplemental products;•    Long term customers tend to be satisfied with their relationship with the company and are less likely to switch to competitors, making market entry or competitors gaining market share difficult;•    Regular customers tend to be less expensive to service, as they are familiar with the processes involved, require less 'education', and are consistent in their order placement;•    Increased customer retention and loyalty makes the employees' jobs easier and more satisfying. In turn, happy employees feed back into higher customer satisfaction in a virtuous circle. Figure 2: The virtuous circle of customer loyaltyFigure 2 represents a high-level example of a virtuous cycle driven by customer satisfaction and loyalty, depicting how superiority in product and service offerings, as well as strong customer support by competent employees, lead to higher sales and ultimately profitability. As stated above, this is not a new concept, but succeeding with it is difficult. It has eluded many a company driven to achieve profitability goals. Of course, for this circle to be virtuous, the customer relationship(s) must be profitable.Trying to maintain the loyalty of unprofitable customers is not a viable business strategy. It is, therefore, important that marketers can assess the profitability of each customer (or customer segment), and either improve or terminate relationships that are not profitable. This means each customer's 'relationship costs' must be understood and compared to their 'relationship revenue'. Customer lifetime value (CLV) is the most commonly used metric here, as it is generally accepted as a representation of exactly how much each customer is worth in monetary terms, and therefore a determinant of exactly how much a service provider should be willing to spend to acquire or retain that customer.CLV models make several simplifying assumptions and often involve the following inputs:•    Churn rate represents the percentage of customers who end their relationship with a company in a given period;•    Retention rate is calculated by subtracting the churn rate percentage from 100;•    Period/horizon equates to the units of time into which a customer relationship can be divided for analysis. A year is the most commonly used period for this purpose. Customer lifetime value is a multi-period calculation, often projecting three to seven years into the future. In practice, analysis beyond this point is viewed as too speculative to be reliable. The model horizon is the number of periods used in the calculation;•    Periodic revenue is the amount of revenue collected from a customer in a given period (though this is often extended across multiple periods into the future to understand lifetime value), such as usage revenue, revenues anticipated from cross and upselling, and often some weighting for referrals by a loyal customer to others; •    Retention cost describes the amount of money the service provider must spend, in a given period, to retain an existing customer. Again, this is often forecast across multiple periods. Retention costs include customer support, billing, promotional incentives and so on;•    Discount rate means the cost of capital used to discount future revenue from a customer. Discounting is an advanced method used in more sophisticated CLV calculations;•    Profit margin is the projected profit as a percentage of revenue for the period. This may be reflected as a percentage of gross or net profit. Again, this is generally projected across the model horizon to understand lifetime value.A strong focus on managing these inputs can help service providers realize stronger customer relationships and profits, but there are some obstacles to overcome in achieving accurate calculations of CLV, such as the complexity of allocating costs across the customer base. There are many costs that serve all customers which must be properly allocated across the base, and often a simple proportional allocation across the whole base or a segment may not accurately reflect the true cost of serving that customer;  This is made worse by the fragmentation of customer information, which is likely to be across a variety of product or operations groups, and may be difficult to aggregate due to different representations.In addition, there is the complexity of account relationships and structures to take into consideration. Complex account structures may not be understood or properly represented. For example, a profitable customer may have a separate account for a second home or another family member, which may appear to be unprofitable. If the service provider cannot relate the two accounts, CLV is not properly represented and any resultant cancellation of the apparently unprofitable account may result in the customer churning from the profitable one.In summary, if service providers are to realize strong customer relationships and their attendant profits, there must be a very strong focus on data management. This needs to be coupled with analytics that help business managers and those who work in customer-facing functions offer highly personalized solutions to customers, while maintaining profitability for the service provider. It's clear that acquiring new customers is expensive. Advertising costs, campaign management expenses, promotional service pricing and discounting, and equipment subsidies make a serious dent in a new customer's profitability. That is especially true given the rising subsidies for Smartphone users, which service providers hope will result in greater profits from profits from data services profitability in future.  The situation is made worse by falling prices and greater competition in mature markets.Customer acquisition through industry consolidation isn't cheap either. A North American service provider spent about $2,000 per subscriber in its acquisition of a smaller company earlier this year. While this has allowed it to leapfrog to become the largest mobile service provider in the country, it required a total investment of more than $28 billion (including assumption of the acquiree's debt).While many operating cost synergies clearly made this deal more attractive to the acquiring company, this is certainly an expensive way to acquire customers: the cost per subscriber in this case is not out of line with the prices others have paid for acquisitions.While growth by acquisition certainly increases overall revenues, it often creates tremendous challenges for profitability. Organic growth through increased customer loyalty and retention is a more effective driver of profit, as well as a stronger predictor of future profitability. Service providers, especially those in mature markets, are increasingly recognizing this and taking steps toward a creating a more personalized, flexible and satisfying experience for their customers.In summary, the clearest path to profitability for companies in virtually all industries is through customer retention and maximization of lifetime value. Service providers would do well to recognize this and focus attention on profitable customer relationships.

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  • CodePlex Daily Summary for Monday, April 09, 2012

    CodePlex Daily Summary for Monday, April 09, 2012Popular ReleasesStyleCop+: StyleCop+ 1.8: Built over StyleCop 4.7.17.0 According to http://stylecop.codeplex.com/workitem/7156, it should be the last version which is released without new features and only for compatibility reasons. Do not forget to Unblock the file after downloading (more details) Stay tuned!Path Copy Copy: 10.1: This release addresses the following work items: 11357 11358 11359 This release is a recommended upgrade, especially for users who didn't install the 10.0.1 version.ExtAspNet: ExtAspNet v3.1.3: ExtAspNet - ?? ExtJS ??? ASP.NET 2.0 ???,????? AJAX ?????????? ExtAspNet ????? ExtJS ??? ASP.NET 2.0 ???,????? AJAX ??????????。 ExtAspNet ??????? JavaScript,?? CSS,?? UpdatePanel,?? ViewState,?? WebServices ???????。 ??????: IE 7.0, Firefox 3.6, Chrome 3.0, Opera 10.5, Safari 3.0+ ????:Apache License 2.0 (Apache) ??:http://extasp.net/ ??:http://bbs.extasp.net/ ??:http://extaspnet.codeplex.com/ ??:http://sanshi.cnblogs.com/ ????: +2012-04-08 v3.1.3 -??Language="zh_TW"?JS???BUG(??)。 +?D...Coding4Fun Tools: Coding4Fun.Phone.Toolkit v1.5.5: New Controls ChatBubble ChatBubbleTextBox OpacityToggleButton New Stuff TimeSpan languages added: RU, SK, CS Expose the physics math from TimeSpanPicker Image Stretch now on buttons Bug Fixes Layout fix so RoundToggleButton and RoundButton are exactly the same Fix for ColorPicker when set via code behind ToastPrompt bug fix with OnNavigatedTo Toast now adjusts its layout if the SIP is up Fixed some issues with Expression Blend supportHarness - Internet Explorer Automation: Harness 2.0.3: support the operation fo frameset, frame and iframe Add commands SwitchFrame GetUrl GoBack GoForward Refresh SetTimeout GetTimeout Rename commands GetActiveWindow to GetActiveBrowser SetActiveWindow to SetActiveBrowser FindWindowAll to FindBrowser NewWindow to NewBrowser GetMajorVersion to GetVersionBetter Explorer: Better Explorer 2.0.0.861 Alpha: - fixed new folder button operation not work well in some situations - removed some unnecessary code like subclassing that is not needed anymore - Added option to make Better Exlorer default (at least for WIN+E operations) - Added option to enable file operation replacements (like Terracopy) to work with Better Explorer - Added some basic usability to "Share" button - Other fixesText Designer Outline Text: Version 2 Preview 2: Added Fake 3D demos for C++ MFC, C# Winform and C# WPFLightFarsiDictionary - ??????? ??? ?????/???????: LightFarsiDictionary - v1: LightFarsiDictionary - v1WPF Application Framework (WAF): WPF Application Framework (WAF) 2.5.0.3: Version: 2.5.0.3 (Milestone 3): This release contains the source code of the WPF Application Framework (WAF) and the sample applications. Requirements .NET Framework 4.0 (The package contains a solution file for Visual Studio 2010) The unit test projects require Visual Studio 2010 Professional Changelog Legend: [B] Breaking change; [O] Marked member as obsolete [O] WAF: Mark the StringBuilderExtensions class as obsolete because the AppendInNewLine method can be replaced with string.Jo...GeoMedia PostGIS data server: PostGIS GDO 1.0.1.2: This is a new version of GeoMeda PostGIS data server which supports user rights. It means that only those feature classes, which the current user has rights to select, are visible in GeoMedia. Issues fixed in this release Fixed problem with renaming and deleting feature classes - IMPORTANT! - the gfeatures view must be recreated so that this issue is completely fixed. The attached script "GFeaturesView2.sql" can be used to accomplish this task. Another way is to drop and recreate the metadat...SkyDrive Connector for SharePoint: SkyDrive Connector for SharePoint: Fixed a few bugs pertaining to live authentication Removed dependency on Shared Documents Removed CallBack web part propertyClosedXML - The easy way to OpenXML: ClosedXML 0.65.2: Aside from many bug fixes we now have Conditional Formatting The conditional formatting was sponsored by http://www.bewing.nl (big thanks) New on v0.65.1 Fixed issue when loading conditional formatting with default values for icon sets New on v0.65.2 Fixed issue loading conditional formatting Improved inserts performanceLiberty: v3.2.0.0 Release 4th April 2012: Change Log-Added -Halo 3 support (invincibility, ammo editing) -Halo 3: ODST support (invincibility, ammo editing) -The file transfer page now shows its progress in the Windows 7 taskbar -"About this build" settings page -Reach Change what an object is carrying -Reach Change which node a carried object is attached to -Reach Object node viewer and exporter -Reach Change which weapons you are carrying from the object editor -Reach Edit the weapon controller of vehicles and turrets -An error dia...MSBuild Extension Pack: April 2012: Release Blog Post The MSBuild Extension Pack April 2012 release provides a collection of over 435 MSBuild tasks. A high level summary of what the tasks currently cover includes the following: System Items: Active Directory, Certificates, COM+, Console, Date and Time, Drives, Environment Variables, Event Logs, Files and Folders, FTP, GAC, Network, Performance Counters, Registry, Services, Sound Code: Assemblies, AsyncExec, CAB Files, Code Signing, DynamicExecute, File Detokenisation, GUID’...DotNetNuke® Community Edition CMS: 06.01.05: Major Highlights Fixed issue that stopped users from creating vocabularies when the portal ID was not zero Fixed issue that caused modules configured to be displayed on all pages to be added to the wrong container in new pages Fixed page quota restriction issue in the Ribbon Bar Removed restriction that would not allow users to use a dash in page names. Now users can create pages with names like "site-map" Fixed issue that was causing the wrong container to be loaded in modules wh...51Degrees.mobi - Mobile Device Detection and Redirection: 2.1.3.1: One Click Install from NuGet Changes to Version 2.1.3.11. [assembly: AllowPartiallyTrustedCallers] has been added back into the AssemblyInfo.cs file to prevent failures with other assemblies in Medium trust environments. 2. The Lite data embedded into the assembly has been updated to include devices from December 2011. The 42 new RingMark properties will return Unknown if RingMark data is not available. Changes to Version 2.1.2.11Code Changes 1. The project is now licenced under the Mozilla...MVC Controls Toolkit: Mvc Controls Toolkit 2.0.0: Added Support for Mvc4 beta and WebApi The SafeqQuery and HttpSafeQuery IQueryable implementations that works as wrappers aroung any IQueryable to protect it from unwished queries. "Client Side" pager specialized in paging javascript data coming either from a remote data source, or from local data. LinQ like fluent javascript api to build queries either against remote data sources, or against local javascript data, with exactly the same interface. There are 3 different query objects exp...nopCommerce. Open source shopping cart (ASP.NET MVC): nopcommerce 2.50: Highlight features & improvements: • Significant performance optimization. • Allow store owners to create several shipments per order. Added a new shipping status: “Partially shipped”. • Pre-order support added. Enables your customers to place a Pre-Order and pay for the item in advance. Displays “Pre-order” button instead of “Buy Now” on the appropriate pages. Makes it possible for customer to buy available goods and Pre-Order items during one session. It can be managed on a product variant ...WiX Toolset: WiX v3.6 RC0: WiX v3.6 RC0 (3.6.2803.0) provides support for VS11 and a more stable Burn engine. For more information see Rob's blog post about the release: http://robmensching.com/blog/posts/2012/4/3/WiX-v3.6-Release-Candidate-Zero-availableSageFrame: SageFrame 2.0: Sageframe is an open source ASP.NET web development framework developed using ASP.NET 3.5 with service pack 1 (sp1) technology. It is designed specifically to help developers build dynamic website by providing core functionality common to most web applications.New ProjectsAprilSpring: Common Framework by pansq and huangghASP.Net MVC Dynamic JS/CSS Script Compression Framework: ASP.Net MVC JS and CSS dynamic script compression and composite script library. Also resolves virtual content urls in CSS files.BANews: ???????????????????,??SQL+Server2008,C#,asp.net????,??????Jquery?CSS+DIV??。??????,?????????????,????????,??????,??。Blazonisation: If have emblem of some state, but don't know anything about it, you can use this tool to resolve your problem. Controle de Campenato: Outro Projeto com alunos da Infnet onde desenvolveremos um controle de campeonato...Controle Financeiro Pessoal Web: Projeto desenvolvido com os alunos do curso Oficial da Microsoft na INFNET. Consiste em controlar as despesas e receitas durante o mes e realizar uma projeção sobre os próximos meses. Bons Estudos, Prof. Carlos PedroCoPro - The .NET Content Provisioning Framework: CoPro makes content management, localization and globalization for ASP.NET Developers easier. It provides a framework which takes care of all management and provisioning activities and the developer only has to create the content and place it on the site. It is developed in C#.cppERF: Class ERF function. Test on VC++ 2008 express, and cygwin.Dev Studio 17 Web-Based FTP Client: Dev Studio 17 Web-Based FTP Client is a web based ftp application built using asp.net, c#.EasyCRMNet: EasyCRMNetEnterpriseLibrary Azure Backing Store: Most developers face difficulties in migrating the application, which is using caching block of Enterprise library, to azure due to unavailability of app fabric cache backing store for Enterprise Library. This library provides an app fabric backing store for enterprise library.Event Aggregator: One of the key aspects in application design is managing dependencies between modules. Good architecture might begin to suffer from strong coupling as long as the project grows. All this affects further development by making it harder to change modules (a change in one module usually forces a ripple effect of changes in other modules), also strongly coupled modules are harder to reuse and test. Message coupling is a good choice in developing loosely coupled architecture. This is the looses...FarhadYazdan-Panah Personal Repsitory: A place for backupFluent Assertions MVC: MVC Extensions for Fluent Assertions library. Source Code is on GitHub: https://github.com/CaseyBurns/FluentAssertions.MVCGboot: GtalkBotGetPicture: GetPicture is a project that get some pictures at a website.It is not good,just use to study.gmfbridge: clone for gmfbridge http://www.gdcl.co.uk/gmfbridge/GoodStore: ??????????,??B/S??,asp.net?sqlserver???,???????,?????????。。。JSLint for Resharper: Adds highlighting of JSLint validation errors to Resharper. kiemtien: Alpha state website, very unstable.nuIDE Kinect Prototype (Experimental): Prototype for Kinect-integrated Visual Studio extension concept. (Not yet alpha - throw away code)PB-LOG-Quick and easy XML logger for .NET: PB-LOG is a quick and easy XML logger for all kink of .NET application. You can insert log associated to a user. There're 4 kind of log: Error, Info, Warning, Event. It's developed in C# 4. There's also a PB-LOG for WP7.PB-LOG-WP7-Quick and easy XML logger for Windows Phone 7: PB-LOG is a quick and easy XML logger for all Windows Phone 7. You can insert log associated to a user. There're 4 kind of log: Error, Info, Warning, Event. It's developed in C# 4.Persian_Calendar_for_Microsoft_Office: "Persian_Calendar_for_Microsoft_Office" makes it easier for Office user group to do their tasks according to time-sheets in IRAN. You'll no longer have to depend on other forms of calendar. It would be developed in any programming language esp C#.Projeto Agenda FPU: Projeto AgendaPS Framework: PS.Framework is an Application Framework to simplify the developement of .NET Applications. It's containing many helpfull classes and functions e.g. an RemotingInterface to simplify the use of .NET Remoting.Quizzer123: Awesome application for quizzes and tests!SharePoint 2010 Automatic Content Database Selection: This solution for SharePoint 2010 automatically selects the smallest content database when you create a new site collection in a web application.SIToFb2: samizdat to bf2 converterSmart Logger: SmartLogger is a web service that can consume exceptions thrown from client applications. The exceptions can be categorized based on severity, applications and exception time stamp. It also includes a search feature to drill down the exceptions log based on search criteria. The release 1.0 will include logging exceptions with search feature. Adding new applications and user right management will follow.Sync Sync: [image:365572] A SharePoint ETL and migration toolTestCuttingStockUsingSolverFoundation: using solver foundation from msft to solve civ e 606 group assignment 2, the cutting stock problem.Vote: ?,???????????????!??,????,?????!WebFurniture: Web-?????????? ??? ?????????????? ????????? ???????yammyy2: yammyy2 zhongjh: ?????????,???????。

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  • Pain Comes Instantly

    - by user701213
    When I look back at recent blog entries – many of which are not all that current (more on where my available writing time is going later) – I am struck by how many of them focus on public policy or legislative issues instead of, say, the latest nefarious cyberattack or exploit (or everyone’s favorite new pastime: coining terms for the Coming Cyberpocalypse: “digital Pearl Harbor” is so 1941). Speaking of which, I personally hope evil hackers from Malefactoria will someday hack into my bathroom scale – which in a future time will be connected to the Internet because, gosh, wouldn’t it be great to have absolutely everything in your life Internet-enabled? – and recalibrate it so I’m 10 pounds thinner. The horror. In part, my focus on public policy is due to an admitted limitation of my skill set. I enjoy reading technical articles about exploits and cybersecurity trends, but writing a blog entry on those topics would take more research than I have time for and, quite honestly, doesn’t play to my strengths. The first rule of writing is “write what you know.” The bigger contributing factor to my recent paucity of blog entries is that more and more of my waking hours are spent engaging in “thrust and parry” activity involving emerging regulations of some sort or other. I’ve opined in earlier blogs about what constitutes good and reasonable public policy so nobody can accuse me of being reflexively anti-regulation. That said, you have so many cycles in the day, and most of us would rather spend it slaying actual dragons than participating in focus groups on whether dragons are really a problem, whether lassoing them (with organic, sustainable and recyclable lassos) is preferable to slaying them – after all, dragons are people, too - and whether we need lasso compliance auditors to make sure lassos are being used correctly and humanely. (A point that seems to evade many rule makers: slaying dragons actually accomplishes something, whereas talking about “approved dragon slaying procedures and requirements” wastes the time of those who are competent to dispatch actual dragons and who were doing so very well without the input of “dragon-slaying theorists.”) Unfortunately for so many of us who would just get on with doing our day jobs, cybersecurity is rapidly devolving into the “focus groups on dragon dispatching” realm, which actual dragons slayers have little choice but to participate in. The general trend in cybersecurity is that powers-that-be – which encompasses groups other than just legislators – are often increasingly concerned and therefore feel they need to Do Something About Cybersecurity. Many seem to believe that if only we had the right amount of regulation and oversight, there would be no data breaches: a breach simply must mean Someone Is At Fault and Needs Supervision. (Leaving aside the fact that we have lots of home invasions despite a) guard dogs b) liberal carry permits c) alarm systems d) etc.) Also note that many well-managed and security-aware organizations, like the US Department of Defense, still get hacked. More specifically, many powers-that-be feel they must direct industry in a multiplicity of ways, up to and including how we actually build and deploy information technology systems. The more prescriptive the requirement, the more regulators or overseers a) can be seen to be doing something b) feel as if they are doing something regardless of whether they are actually doing something useful or cost effective. Note: an unfortunate concomitant of Doing Something is that often the cure is worse than the ailment. That is, doing what overseers want creates unfortunate byproducts that they either didn’t foresee or worse, don’t care about. After all, the logic goes, we Did Something. Prescriptive practice in the IT industry is problematic for a number of reasons. For a start, prescriptive guidance is really only appropriate if: • It is cost effective• It is “current” (meaning, the guidance doesn’t require the use of the technical equivalent of buggy whips long after horse-drawn transportation has become passé)*• It is practical (that is, pragmatic, proven and effective in the real world, not theoretical and unproven)• It solves the right problem With the above in mind, heading up the list of “you must be joking” regulations are recent disturbing developments in the Payment Card Industry (PCI) world. I’d like to give PCI kahunas the benefit of the doubt about their intentions, except that efforts by Oracle among others to make them aware of “unfortunate side effects of your requirements” – which is as tactful I can be for reasons that I believe will become obvious below - have gone, to-date, unanswered and more importantly, unchanged. A little background on PCI before I get too wound up. In 2008, the Payment Card Industry (PCI) Security Standards Council (SSC) introduced the Payment Application Data Security Standard (PA-DSS). That standard requires vendors of payment applications to ensure that their products implement specific requirements and undergo security assessment procedures. In order to have an application listed as a Validated Payment Application (VPA) and available for use by merchants, software vendors are required to execute the PCI Payment Application Vendor Release Agreement (VRA). (Are you still with me through all the acronyms?) Beginning in August 2010, the VRA imposed new obligations on vendors that are extraordinary and extraordinarily bad, short-sighted and unworkable. Specifically, PCI requires vendors to disclose (dare we say “tell all?”) to PCI any known security vulnerabilities and associated security breaches involving VPAs. ASAP. Think about the impact of that. PCI is asking a vendor to disclose to them: • Specific details of security vulnerabilities • Including exploit information or technical details of the vulnerability • Whether or not there is any mitigation available (as in a patch) PCI, in turn, has the right to blab about any and all of the above – specifically, to distribute all the gory details of what is disclosed - to the PCI SSC, qualified security assessors (QSAs), and any affiliate or agent or adviser of those entities, who are in turn permitted to share it with their respective affiliates, agents, employees, contractors, merchants, processors, service providers and other business partners. This assorted crew can’t be more than, oh, hundreds of thousands of entities. Does anybody believe that several hundred thousand people can keep a secret? Or that several hundred thousand people are all equally trustworthy? Or that not one of the people getting all that information would blab vulnerability details to a bad guy, even by accident? Or be a bad guy who uses the information to break into systems? (Wait, was that the Easter Bunny that just hopped by? Bringing world peace, no doubt.) Sarcasm aside, common sense tells us that telling lots of people a secret is guaranteed to “unsecret” the secret. Notably, being provided details of a vulnerability (without a patch) is of little or no use to companies running the affected application. Few users have the technological sophistication to create a workaround, and even if they do, most workarounds break some other functionality in the application or surrounding environment. Also, given the differences among corporate implementations of any application, it is highly unlikely that a single workaround is going to work for all corporate users. So until a patch is developed by the vendor, users remain at risk of exploit: even more so if the details of vulnerability have been widely shared. Sharing that information widely before a patch is available therefore does not help users, and instead helps only those wanting to exploit known security bugs. There’s a shocker for you. Furthermore, we already know that insider information about security vulnerabilities inevitably leaks, which is why most vendors closely hold such information and limit dissemination until a patch is available (and frequently limit dissemination of technical details even with the release of a patch). That’s the industry norm, not that PCI seems to realize or acknowledge that. Why would anybody release a bunch of highly technical exploit information to a cast of thousands, whose only “vetting” is that they are members of a PCI consortium? Oracle has had personal experience with this problem, which is one reason why information on security vulnerabilities at Oracle is “need to know” (we use our own row level access control to limit access to security bugs in our bug database, and thus less than 1% of development has access to this information), and we don’t provide some customers with more information than others or with vulnerability information and/or patches earlier than others. Failure to remember “insider information always leaks” creates problems in the general case, and has created problems for us specifically. A number of years ago, one of the UK intelligence agencies had information about a non-public security vulnerability in an Oracle product that they circulated among other UK and Commonwealth defense and intelligence entities. Nobody, it should be pointed out, bothered to report the problem to Oracle, even though only Oracle could produce a patch. The vulnerability was finally reported to Oracle by (drum roll) a US-based commercial company, to whom the information had leaked. (Note: every time I tell this story, the MI-whatever agency that created the problem gets a bit shirty with us. I know they meant well and have improved their vulnerability handling/sharing processes but, dudes, next time you find an Oracle vulnerability, try reporting it to us first before blabbing to lots of people who can’t actually fix the problem. Thank you!) Getting back to PCI: clearly, these new disclosure obligations increase the risk of exploitation of a vulnerability in a VPA and thus, of misappropriation of payment card data and customer information that a VPA processes, stores or transmits. It stands to reason that VRA’s current requirement for the widespread distribution of security vulnerability exploit details -- at any time, but particularly before a vendor can issue a patch or a workaround -- is very poor public policy. It effectively publicizes information of great value to potential attackers while not providing compensating benefits - actually, any benefits - to payment card merchants or consumers. In fact, it magnifies the risk to payment card merchants and consumers. The risk is most prominent in the time before a patch has been released, since customers often have little option but to continue using an application or system despite the risks. However, the risk is not limited to the time before a patch is issued: customers often need days, or weeks, to apply patches to systems, based upon the complexity of the issue and dependence on surrounding programs. Rather than decreasing the available window of exploit, this requirement increases the available window of exploit, both as to time available to exploit a vulnerability and the ease with which it can be exploited. Also, why would hackers focus on finding new vulnerabilities to exploit if they can get “EZHack” handed to them in such a manner: a) a vulnerability b) in a payment application c) with exploit code: the “Hacking Trifecta!“ It’s fair to say that this is probably the exact opposite of what PCI – or any of us – would want. Established industry practice concerning vulnerability handling avoids the risks created by the VRA’s vulnerability disclosure requirements. Specifically, the norm is not to release information about a security bug until the associated patch (or a pretty darn good workaround) has been issued. Once a patch is available, the notice to the user community is a high-level communication discussing the product at issue, the level of risk associated with the vulnerability, and how to apply the patch. The notices do not include either the specific customers affected by the vulnerability or forensic reports with maps of the exploit (both of which are required by the current VRA). In this way, customers have the tools they need to prioritize patching and to help prevent an attack, and the information released does not increase the risk of exploit. Furthermore, many vendors already use industry standards for vulnerability description: Common Vulnerability Enumeration (CVE) and Common Vulnerability Scoring System (CVSS). CVE helps ensure that customers know which particular issues a patch addresses and CVSS helps customers determine how severe a vulnerability is on a relative scale. Industry already provides the tools customers need to know what the patch contains and how bad the problem is that the patch remediates. So, what’s a poor vendor to do? Oracle is reaching out to other vendors subject to PCI and attempting to enlist then in a broad effort to engage PCI in rethinking (that is, eradicating) these requirements. I would therefore urge all who care about this issue, but especially those in the vendor community whose applications are subject to PCI and who may not have know they were being asked to tell-all to PCI and put their customers at risk, to do one of the following: • Contact PCI with your concerns• Contact Oracle (we are looking for vendors to sign our statement of concern)• And make sure you tell your customers that you have to rat them out to PCI if there is a breach involving the payment application I like to be charitable and say “PCI meant well” but in as important a public policy issue as what you disclose about vulnerabilities, to whom and when, meaning well isn’t enough. We need to do well. PCI, as regards this particular issue, has not done well, and has compounded the error by thus far being nonresponsive to those of us who have labored mightily to try to explain why they might want to rethink telling the entire planet about security problems with no solutions. By Way of Explanation… Non-related to PCI whatsoever, and the explanation for why I have not been blogging a lot recently, I have been working on Other Writing Venues with my sister Diane (who has also worked in the tech sector, inflicting upgrades on unsuspecting and largely ungrateful end users). I am pleased to note that we have recently (self-)published the first in the Miss Information Technology Murder Mystery series, Outsourcing Murder. The genre might best be described as “chick lit meets geek scene.” Our sisterly nom de plume is Maddi Davidson and (shameless plug follows): you can order the paper version of the book on Amazon, or the Kindle or Nook versions on www.amazon.com or www.bn.com, respectively. From our book jacket: Emma Jones, a 20-something IT consultant, is working on an outsourcing project at Tahiti Tacos, a restaurant chain offering Polynexican cuisine: refried poi, anyone? Emma despises her boss Padmanabh, a brilliant but arrogant partner in GD Consulting. When Emma discovers His-Royal-Padness’s body (verdict: death by cricket bat), she becomes a suspect.With her overprotective family and her best friend Stacey providing endless support and advice, Emma stumbles her way through an investigation of Padmanabh’s murder, bolstered by fusion food feeding frenzies, endless cups of frou-frou coffee and serious surfing sessions. While Stacey knows a PI who owes her a favor, landlady Magda urges Emma to tart up her underwear drawer before the next cute cop with a search warrant arrives. Emma’s mother offers to fix her up with a PhD student at Berkeley and showers her with self-defense gizmos while her old lover Keoni beckons from Hawai’i. And everyone, even Shaun the barista, knows a good lawyer. Book 2, Denial of Service, is coming out this summer. * Given the rate of change in technology, today’s “thou shalts” are easily next year’s “buggy whip guidance.”

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  • C#/.NET Little Wonders: The Useful But Overlooked Sets

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  Today we will be looking at two set implementations in the System.Collections.Generic namespace: HashSet<T> and SortedSet<T>.  Even though most people think of sets as mathematical constructs, they are actually very useful classes that can be used to help make your application more performant if used appropriately. A Background From Math In mathematical terms, a set is an unordered collection of unique items.  In other words, the set {2,3,5} is identical to the set {3,5,2}.  In addition, the set {2, 2, 4, 1} would be invalid because it would have a duplicate item (2).  In addition, you can perform set arithmetic on sets such as: Intersections: The intersection of two sets is the collection of elements common to both.  Example: The intersection of {1,2,5} and {2,4,9} is the set {2}. Unions: The union of two sets is the collection of unique items present in either or both set.  Example: The union of {1,2,5} and {2,4,9} is {1,2,4,5,9}. Differences: The difference of two sets is the removal of all items from the first set that are common between the sets.  Example: The difference of {1,2,5} and {2,4,9} is {1,5}. Supersets: One set is a superset of a second set if it contains all elements that are in the second set. Example: The set {1,2,5} is a superset of {1,5}. Subsets: One set is a subset of a second set if all the elements of that set are contained in the first set. Example: The set {1,5} is a subset of {1,2,5}. If We’re Not Doing Math, Why Do We Care? Now, you may be thinking: why bother with the set classes in C# if you have no need for mathematical set manipulation?  The answer is simple: they are extremely efficient ways to determine ownership in a collection. For example, let’s say you are designing an order system that tracks the price of a particular equity, and once it reaches a certain point will trigger an order.  Now, since there’s tens of thousands of equities on the markets, you don’t want to track market data for every ticker as that would be a waste of time and processing power for symbols you don’t have orders for.  Thus, we just want to subscribe to the stock symbol for an equity order only if it is a symbol we are not already subscribed to. Every time a new order comes in, we will check the list of subscriptions to see if the new order’s stock symbol is in that list.  If it is, great, we already have that market data feed!  If not, then and only then should we subscribe to the feed for that symbol. So far so good, we have a collection of symbols and we want to see if a symbol is present in that collection and if not, add it.  This really is the essence of set processing, but for the sake of comparison, let’s say you do a list instead: 1: // class that handles are order processing service 2: public sealed class OrderProcessor 3: { 4: // contains list of all symbols we are currently subscribed to 5: private readonly List<string> _subscriptions = new List<string>(); 6:  7: ... 8: } Now whenever you are adding a new order, it would look something like: 1: public PlaceOrderResponse PlaceOrder(Order newOrder) 2: { 3: // do some validation, of course... 4:  5: // check to see if already subscribed, if not add a subscription 6: if (!_subscriptions.Contains(newOrder.Symbol)) 7: { 8: // add the symbol to the list 9: _subscriptions.Add(newOrder.Symbol); 10: 11: // do whatever magic is needed to start a subscription for the symbol 12: } 13:  14: // place the order logic! 15: } What’s wrong with this?  In short: performance!  Finding an item inside a List<T> is a linear - O(n) – operation, which is not a very performant way to find if an item exists in a collection. (I used to teach algorithms and data structures in my spare time at a local university, and when you began talking about big-O notation you could immediately begin to see eyes glossing over as if it was pure, useless theory that would not apply in the real world, but I did and still do believe it is something worth understanding well to make the best choices in computer science). Let’s think about this: a linear operation means that as the number of items increases, the time that it takes to perform the operation tends to increase in a linear fashion.  Put crudely, this means if you double the collection size, you might expect the operation to take something like the order of twice as long.  Linear operations tend to be bad for performance because they mean that to perform some operation on a collection, you must potentially “visit” every item in the collection.  Consider finding an item in a List<T>: if you want to see if the list has an item, you must potentially check every item in the list before you find it or determine it’s not found. Now, we could of course sort our list and then perform a binary search on it, but sorting is typically a linear-logarithmic complexity – O(n * log n) - and could involve temporary storage.  So performing a sort after each add would probably add more time.  As an alternative, we could use a SortedList<TKey, TValue> which sorts the list on every Add(), but this has a similar level of complexity to move the items and also requires a key and value, and in our case the key is the value. This is why sets tend to be the best choice for this type of processing: they don’t rely on separate keys and values for ordering – so they save space – and they typically don’t care about ordering – so they tend to be extremely performant.  The .NET BCL (Base Class Library) has had the HashSet<T> since .NET 3.5, but at that time it did not implement the ISet<T> interface.  As of .NET 4.0, HashSet<T> implements ISet<T> and a new set, the SortedSet<T> was added that gives you a set with ordering. HashSet<T> – For Unordered Storage of Sets When used right, HashSet<T> is a beautiful collection, you can think of it as a simplified Dictionary<T,T>.  That is, a Dictionary where the TKey and TValue refer to the same object.  This is really an oversimplification, but logically it makes sense.  I’ve actually seen people code a Dictionary<T,T> where they store the same thing in the key and the value, and that’s just inefficient because of the extra storage to hold both the key and the value. As it’s name implies, the HashSet<T> uses a hashing algorithm to find the items in the set, which means it does take up some additional space, but it has lightning fast lookups!  Compare the times below between HashSet<T> and List<T>: Operation HashSet<T> List<T> Add() O(1) O(1) at end O(n) in middle Remove() O(1) O(n) Contains() O(1) O(n)   Now, these times are amortized and represent the typical case.  In the very worst case, the operations could be linear if they involve a resizing of the collection – but this is true for both the List and HashSet so that’s a less of an issue when comparing the two. The key thing to note is that in the general case, HashSet is constant time for adds, removes, and contains!  This means that no matter how large the collection is, it takes roughly the exact same amount of time to find an item or determine if it’s not in the collection.  Compare this to the List where almost any add or remove must rearrange potentially all the elements!  And to find an item in the list (if unsorted) you must search every item in the List. So as you can see, if you want to create an unordered collection and have very fast lookup and manipulation, the HashSet is a great collection. And since HashSet<T> implements ICollection<T> and IEnumerable<T>, it supports nearly all the same basic operations as the List<T> and can use the System.Linq extension methods as well. All we have to do to switch from a List<T> to a HashSet<T>  is change our declaration.  Since List and HashSet support many of the same members, chances are we won’t need to change much else. 1: public sealed class OrderProcessor 2: { 3: private readonly HashSet<string> _subscriptions = new HashSet<string>(); 4:  5: // ... 6:  7: public PlaceOrderResponse PlaceOrder(Order newOrder) 8: { 9: // do some validation, of course... 10: 11: // check to see if already subscribed, if not add a subscription 12: if (!_subscriptions.Contains(newOrder.Symbol)) 13: { 14: // add the symbol to the list 15: _subscriptions.Add(newOrder.Symbol); 16: 17: // do whatever magic is needed to start a subscription for the symbol 18: } 19: 20: // place the order logic! 21: } 22:  23: // ... 24: } 25: Notice, we didn’t change any code other than the declaration for _subscriptions to be a HashSet<T>.  Thus, we can pick up the performance improvements in this case with minimal code changes. SortedSet<T> – Ordered Storage of Sets Just like HashSet<T> is logically similar to Dictionary<T,T>, the SortedSet<T> is logically similar to the SortedDictionary<T,T>. The SortedSet can be used when you want to do set operations on a collection, but you want to maintain that collection in sorted order.  Now, this is not necessarily mathematically relevant, but if your collection needs do include order, this is the set to use. So the SortedSet seems to be implemented as a binary tree (possibly a red-black tree) internally.  Since binary trees are dynamic structures and non-contiguous (unlike List and SortedList) this means that inserts and deletes do not involve rearranging elements, or changing the linking of the nodes.  There is some overhead in keeping the nodes in order, but it is much smaller than a contiguous storage collection like a List<T>.  Let’s compare the three: Operation HashSet<T> SortedSet<T> List<T> Add() O(1) O(log n) O(1) at end O(n) in middle Remove() O(1) O(log n) O(n) Contains() O(1) O(log n) O(n)   The MSDN documentation seems to indicate that operations on SortedSet are O(1), but this seems to be inconsistent with its implementation and seems to be a documentation error.  There’s actually a separate MSDN document (here) on SortedSet that indicates that it is, in fact, logarithmic in complexity.  Let’s put it in layman’s terms: logarithmic means you can double the collection size and typically you only add a single extra “visit” to an item in the collection.  Take that in contrast to List<T>’s linear operation where if you double the size of the collection you double the “visits” to items in the collection.  This is very good performance!  It’s still not as performant as HashSet<T> where it always just visits one item (amortized), but for the addition of sorting this is a good thing. Consider the following table, now this is just illustrative data of the relative complexities, but it’s enough to get the point: Collection Size O(1) Visits O(log n) Visits O(n) Visits 1 1 1 1 10 1 4 10 100 1 7 100 1000 1 10 1000   Notice that the logarithmic – O(log n) – visit count goes up very slowly compare to the linear – O(n) – visit count.  This is because since the list is sorted, it can do one check in the middle of the list, determine which half of the collection the data is in, and discard the other half (binary search).  So, if you need your set to be sorted, you can use the SortedSet<T> just like the HashSet<T> and gain sorting for a small performance hit, but it’s still faster than a List<T>. Unique Set Operations Now, if you do want to perform more set-like operations, both implementations of ISet<T> support the following, which play back towards the mathematical set operations described before: IntersectWith() – Performs the set intersection of two sets.  Modifies the current set so that it only contains elements also in the second set. UnionWith() – Performs a set union of two sets.  Modifies the current set so it contains all elements present both in the current set and the second set. ExceptWith() – Performs a set difference of two sets.  Modifies the current set so that it removes all elements present in the second set. IsSupersetOf() – Checks if the current set is a superset of the second set. IsSubsetOf() – Checks if the current set is a subset of the second set. For more information on the set operations themselves, see the MSDN description of ISet<T> (here). What Sets Don’t Do Don’t get me wrong, sets are not silver bullets.  You don’t really want to use a set when you want separate key to value lookups, that’s what the IDictionary implementations are best for. Also sets don’t store temporal add-order.  That is, if you are adding items to the end of a list all the time, your list is ordered in terms of when items were added to it.  This is something the sets don’t do naturally (though you could use a SortedSet with an IComparer with a DateTime but that’s overkill) but List<T> can. Also, List<T> allows indexing which is a blazingly fast way to iterate through items in the collection.  Iterating over all the items in a List<T> is generally much, much faster than iterating over a set. Summary Sets are an excellent tool for maintaining a lookup table where the item is both the key and the value.  In addition, if you have need for the mathematical set operations, the C# sets support those as well.  The HashSet<T> is the set of choice if you want the fastest possible lookups but don’t care about order.  In contrast the SortedSet<T> will give you a sorted collection at a slight reduction in performance.   Technorati Tags: C#,.Net,Little Wonders,BlackRabbitCoder,ISet,HashSet,SortedSet

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  • The Changing Face of PASS

    - by Bill Graziano
    I’m starting my sixth year on the PASS Board.  I served two years as the Program Director, two years as the Vice-President of Marketing and I’m starting my second year as the Executive Vice-President of Finance.  There’s a pretty good chance that if PASS has done something you don’t like or is doing something you don’t like, that I’m involved in one way or another. Andy Leonard asked in a comment on his blog if the Board had ever reversed itself based on community input.  He asserted that it hadn’t.  I disagree.  I’m not going to try and list all the changes we make inside portfolios based on feedback from and meetings with the community.  I’m going to focus on major governance issues since I was elected to the Board. Management Company The first big change was our management company.  Our old management company had a standard approach to running a non-profit.  It worked well when PASS was launched.  Having a ready-made structure and process to run the organization enabled the organization to grow quickly.  As time went on we were limited in some of the things we wanted to do.  The more involved you were with PASS, the more you saw these limitations.  Key volunteers were regularly providing feedback that they wanted certain changes that were difficult for us to accomplish.  The Board at that time wanted changes that were difficult or impossible to accomplish under that structure. This was not a simple change.  Imagine a $2.5 million dollar company letting all its employees go on a Friday and starting with a new staff on Monday.  We also had a very narrow window to accomplish that so that we wouldn’t affect the Summit – our only source of revenue.  We spent the year after the change rebuilding processes and putting on the Summit in Denver.  That’s a concrete example of a huge change that PASS made to better serve its members.  And it was a change that many in the community were telling us we needed to make. Financials We heard regularly from our members that they wanted our financials posted.  Today on our web site you can find audited financials going back to 2004.  We publish our budget at the start of each year.  If you ask a question about the financials on the PASS site I do my best to answer it.  I’m also trying to do a better job answering financial questions posted in other locations.  (And yes, I know I owe a few of you some blog posts.) That’s another concrete example of a change that our members asked for that the Board agreed was a good decision. Minutes When I started on the Board the meeting minutes were very limited.  The minutes from a two day Board meeting might fit on one page.  I think we did the bare minimum we were legally required to do.  Today Board meeting minutes run from 5 to 12 pages and go into incredible detail on what we talk about.  There are certain topics that are NDA but where possible we try to list the topic we discussed but that the actual discussion was under NDA.  We also publish the agenda of Board meetings ahead of time. This is another specific example where input from the community influenced the decision.  It was certainly easier to have limited minutes but I think the extra effort helps our members understand what’s going on. Board Q&A At the 2009 Summit the Board held its first public Q&A with our members.  We’d always been available individually to answer questions.  There’s a benefit to getting us all in one room and asking the really hard questions to watch us squirm.  We learn what questions we don’t have good answers for.  We get to see how many people in the crowd look interested in the various questions and answers. I don’t recall the genesis of how this came about.  I’m fairly certain there was some community pressure though. Board Votes Until last November, the Board only reported the vote totals and not how individual Board members voted.  That was one of the topics at a great lunch I had with Tim Mitchell and Kendal van Dyke at the Summit.  That was also the topic of the first question asked at the Board Q&A by Kendal.  Kendal expressed his opposition to to anonymous votes clearly and passionately and without trying to paint anyone into a corner.  Less than 24 hours later the PASS Board voted to make individual votes public unless the topic was under NDA.  That’s another area where the Board decided to change based on feedback from our members. Summit Location While this isn’t actually a governance issue it is one of the more public decisions we make that has taken some public criticism.  There is a significant portion of our members that want the Summit near them.  There is a significant portion of our members that like the Summit in Seattle.  There is a significant portion of our members that think it should move around the country.  I was one that felt strongly that there were significant, tangible benefits to our attendees to being in Seattle every year.  I’m also one that has been swayed by some very compelling arguments that we need to have at least one outside Seattle and then revisit the decision.  I can’t tell you how the Board will vote but I know the opinion of our members weighs heavily on the decision. Elections And that brings us to the grand-daddy of all governance issues.  My thesis for this blog post is that the PASS Board has implemented policy changes in response to member feedback.  It isn’t to defend or criticize our election process.  It’s just to say that is has been under going continuous change since I’ve been on the Board.  I ran for the Board in the fall of 2005.  I don’t know much about what happened before then.  I was actively volunteering for PASS for four years prior to that as a chapter leader and on the program committee.  I don’t recall any complaints about elections but that doesn’t mean they didn’t occur.  The questions from the Nominating Committee (NomCom) were trivial and the selection process rudimentary (For example, “Tell us about your accomplishments”).  I don’t even remember who I ran against or how many other people ran.  I ran for the VP of Marketing in the fall of 2007.  I don’t recall any significant changes the Board made in the election process for that election.  I think a lot of the changes in 2007 came from us asking the management company to work on the election process.  I was expecting a similar set of puff ball questions from my previous election.  Boy, was I in for a shock.  The NomCom had found a much better set of questions and really made the interview portion difficult.  The questions were much more behavioral in nature.  I’d already written about my vision for PASS and my goals.  They wanted to know how I handled adversity, how I handled criticism, how I handled conflict, how I handled troublesome volunteers, how I motivated people and how I responded to motivation. And many, many other things. They grilled me for over an hour.  I’ve done a fair bit of technical sales in my time.  I feel I speak well under pressure addressing pointed questions.  This interview intentionally put me under pressure.  In addition to wanting to know about my interpersonal skills, my work experience, my volunteer experience and my supervisory experience they wanted to see how I’d do under pressure.  They wanted to see who would respond under pressure and who wouldn’t.  It was a bit of a shock. That was the first big change I remember in the election process.  I know there were other improvements around the process but none of them stick in my mind quite like the unexpected hour-long grilling. The next big change I remember was after the 2009 elections.  Andy Warren was unhappy with the election process and wanted to make some changes.  He worked with Hannes at HQ and they came up with a better set of processes.  I think Andy moved PASS in the right direction.  Nonetheless, after the 2010 election even more people were very publicly clamoring for changes to our election process.  In August of 2010 we had a choice to make.  There were numerous bloggers criticizing the Board and our upcoming election.  The easy change would be to announce that we were changing the process in a way that would satisfy our critics.  I believe that a knee-jerk response to criticism is seldom correct. Instead the Board spent August and September and October and November listening to the community.  I visited two SQLSaturdays and asked questions of everyone I could.  I attended chapter meetings and asked questions of as many people as they’d let me.  At Summit I made it a point to introduce myself to strangers and ask them about the election.  At every breakfast I’d sit down at a table full of strangers and ask about the election.  I’m happy to say that I left most tables arguing about the election.  Most days I managed to get 2 or 3 breakfasts in. I spent less time talking to people that had already written about the election.  They were already expressing their opinion.  I wanted to talk to people that hadn’t spoken up.  I wanted to know what the silent majority thought.  The Board all attended the Q&A session where our members expressed their concerns about a variety of issues including the election. The PASS Board also chose to create the Election Review Committee.  We wanted people from the community that had been involved with PASS to look at our election process with fresh eyes while listening to what the community had to say and give us some advice on how we could improve the process.  I’m a part of this as is Andy Warren.  None of the other members are on the Board.  I’ve sat in numerous calls and interviews with this group and attended an open meeting at the Summit.  We asked anyone that wanted to discuss the election to come speak with us.  The ERC held an open meeting at the Summit and invited anyone to attend.  There are forums on the ERC web site where we’ve invited people to participate.  The ERC has reached to key people involved in recent elections.  The years that I haven’t mentioned also saw minor improvements in the election process.  Off the top of my head I don’t recall what exact changes were made each year.  Specifically since the 2010 election we’ve gone out of our way to seek input from the community about the process.  I’m not sure what more we could have done to invite feedback from the community. I think to say that we haven’t “fixed” the election process isn’t a fair criticism at this time.  We haven’t rushed any changes through the process.  If you don’t see any changes in our election process in July or August then I think it’s fair to criticize us for ignoring the community or ask for an explanation for what we’ve done. In Summary Andy’s main point was that the PASS Board hasn’t changed in response to our members wishes.  I think I’ve shown that time and time again the PASS Board has changed in response to what our members want.  There are only two outstanding issues: Summit location and elections.  The 2013 Summit location hasn’t been decided yet.  Our work on the elections is also in progress.  And at every step in the election review we’ve gone out of our way to listen to the community and incorporate their feedback on the process. I also hope I’m not encouraging everyone that wants some change in the organization to organize a “blog rush” against the Board.  We take public suggestions very seriously but we also take the time to evaluate those suggestions and learn what the rest of our members think and make a measured decision.

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  • .NET Code Evolution

    - by Alois Kraus
    Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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