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  • Error data: line 2 column 1 when using pycurl with gzip stream

    - by Sagar Hatekar
    Thanks for reading. Background: I am trying to read a streaming API feed that returns data in JSON format, and then storing this data to a pymongo collection. The streaming API requires a "Accept-Encoding" : "Gzip" header. What's happening: Code fails on json.loads and outputs - Extra data: line 2 column 1 - line 4 column 1 (char 1891 - 5597) (Refer Error Log below) This does NOT happen while parsing every JSON object - it happens at random. My guess is I am encountering some weird JSON object after every "x" proper JSON objects. I did reference how to use pycurl if requested data is sometimes gzipped, sometimes not? and Encoding error while deserializing a json object from Google but so far have been unsuccessful at resolving this error. Could someone please help me out here? Error Log: Note: The raw dump of the JSON object below is basically using the repr() method. '{"id":"tag:search.twitter.com,2005:207958320747782146","objectType":"activity","actor":{"objectType":"person","id":"id:twitter.com:493653150","link":"http://www.twitter.com/Deathnews_7_24","displayName":"Death News 7/24","postedTime":"2012-02-16T01:30:12.000Z","image":"http://a0.twimg.com/profile_images/1834408513/deathnewstwittersquare_normal.jpg","summary":"Crashes, Murders, Suicides, Accidents, Crime and Naturals Death News From All Around World","links":[{"href":"http://www.facebook.com/DeathNews724","rel":"me"}],"friendsCount":56,"followersCount":14,"listedCount":1,"statusesCount":1029,"twitterTimeZone":null,"utcOffset":null,"preferredUsername":"Deathnews_7_24","languages":["tr"]},"verb":"post","postedTime":"2012-05-30T22:15:02.000Z","generator":{"displayName":"web","link":"http://twitter.com"},"provider":{"objectType":"service","displayName":"Twitter","link":"http://www.twitter.com"},"link":"http://twitter.com/Deathnews_7_24/statuses/207958320747782146","body":"Kathi Kamen Goldmark, Writers\xe2\x80\x99 Catalyst, Dies at 63 http://t.co/WBsNlNtA","object":{"objectType":"note","id":"object:search.twitter.com,2005:207958320747782146","summary":"Kathi Kamen Goldmark, Writers\xe2\x80\x99 Catalyst, Dies at 63 http://t.co/WBsNlNtA","link":"http://twitter.com/Deathnews_7_24/statuses/207958320747782146","postedTime":"2012-05-30T22:15:02.000Z"},"twitter_entities":{"urls":[{"display_url":"nytimes.com/2012/05/30/boo\xe2\x80\xa6","indices":[52,72],"expanded_url":"http://www.nytimes.com/2012/05/30/books/kathi-kamen-goldmark-writers-catalyst-dies-at-63.html","url":"http://t.co/WBsNlNtA"}],"hashtags":[],"user_mentions":[]},"gnip":{"language":{"value":"en"},"matching_rules":[{"value":"url_contains: nytimes.com","tag":null}],"klout_score":11,"urls":[{"url":"http://t.co/WBsNlNtA","expanded_url":"http://www.nytimes.com/2012/05/30/books/kathi-kamen-goldmark-writers-catalyst-dies-at-63.html?_r=1"}]}}\r\n{"id":"tag:search.twitter.com,2005:207958321003638785","objectType":"activity","actor":{"objectType":"person","id":"id:twitter.com:178760897","link":"http://www.twitter.com/Mobanu","displayName":"Donald Ochs","postedTime":"2010-08-15T16:33:56.000Z","image":"http://a0.twimg.com/profile_images/1493224811/small_mobany_Logo_normal.jpg","summary":"","links":[{"href":"http://www.mobanuweightloss.com","rel":"me"}],"friendsCount":10272,"followersCount":9698,"listedCount":30,"statusesCount":725,"twitterTimeZone":"Mountain Time (US & Canada)","utcOffset":"-25200","preferredUsername":"Mobanu","languages":["en"],"location":{"objectType":"place","displayName":"Crested Butte, Colorado"}},"verb":"post","postedTime":"2012-05-30T22:15:02.000Z","generator":{"displayName":"twitterfeed","link":"http://twitterfeed.com"},"provider":{"objectType":"service","displayName":"Twitter","link":"http://www.twitter.com"},"link":"http://twitter.com/Mobanu/statuses/207958321003638785","body":"Mobanu: Can Exercise Be Bad for You?: Researchers have found evidence that some people who exercise do worse on ... http://t.co/mTsQlNQO","object":{"objectType":"note","id":"object:search.twitter.com,2005:207958321003638785","summary":"Mobanu: Can Exercise Be Bad for You?: Researchers have found evidence that some people who exercise do worse on ... http://t.co/mTsQlNQO","link":"http://twitter.com/Mobanu/statuses/207958321003638785","postedTime":"2012-05-30T22:15:02.000Z"},"twitter_entities":{"urls":[{"display_url":"nyti.ms/KUmmMa","indices":[116,136],"expanded_url":"http://nyti.ms/KUmmMa","url":"http://t.co/mTsQlNQO"}],"hashtags":[],"user_mentions":[]},"gnip":{"language":{"value":"en"},"matching_rules":[{"value":"url_contains: nytimes.com","tag":null}],"klout_score":12,"urls":[{"url":"http://t.co/mTsQlNQO","expanded_url":"http://well.blogs.nytimes.com/2012/05/30/can-exercise-be-bad-for-you/?utm_medium=twitter&utm_source=twitterfeed"}]}}\r\n' json exception: Extra data: line 2 column 1 - line 4 column 1 (char 1891 - 5597) Header Output: HTTP/1.1 200 OK Content-Type: application/json; charset=UTF-8 Vary: Accept-Encoding Date: Wed, 30 May 2012 22:14:48 UTC Connection: close Transfer-Encoding: chunked Content-Encoding: gzip get_stream.py: #!/usr/bin/env python import sys import pycurl import json import pymongo STREAM_URL = "https://stream.test.com:443/accounts/publishers/twitter/streams/track/Dev.json" AUTH = "userid:passwd" DB_HOST = "127.0.0.1" DB_NAME = "stream_test" class StreamReader: def __init__(self): try: self.count = 0 self.buff = "" self.mongo = pymongo.Connection(DB_HOST) self.db = self.mongo[DB_NAME] self.raw_tweets = self.db["raw_tweets_gnip"] self.conn = pycurl.Curl() self.conn.setopt(pycurl.ENCODING, 'gzip') self.conn.setopt(pycurl.URL, STREAM_URL) self.conn.setopt(pycurl.USERPWD, AUTH) self.conn.setopt(pycurl.WRITEFUNCTION, self.on_receive) self.conn.setopt(pycurl.HEADERFUNCTION, self.header_rcvd) while True: self.conn.perform() except Exception as ex: print "error ocurred : %s" % str(ex) def header_rcvd(self, header_data): print header_data def on_receive(self, data): temp_data = data self.buff += data if data.endswith("\r\n") and self.buff.strip(): try: tweet = json.loads(self.buff, encoding = 'UTF-8') self.buff = "" if tweet: try: self.raw_tweets.insert(tweet) except Exception as insert_ex: print "Error inserting tweet: %s" % str(insert_ex) self.count += 1 if self.count % 10 == 0: print "inserted "+str(self.count)+" tweets" except Exception as json_ex: print "json exception: %s" % str(json_ex) print repr(temp_data) stream = StreamReader()

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  • Day 2 - Game Design Documentation

    - by dapostolov
    So yesterday I didn't cut any code for my game but I was able to do a tiny bit of research on the XNA Game Development Technology and the communities out there and do you know what? I feel I'm a bit closer to my goal. The bad news is today I didn't cut code either. However, not all is lost because I wanted to get my ideas on paper and today I just did that.  Today, I began to jot down notes about the game and how I felt the visual elements would interact with each other. Unlike my workplace, my personal level of documentation is nothing more than a task list or a mind map of my ideas; it helps me streamline my solutions quiet effectively and circumvent the long process of articulating each thought to the n-th degree. I truly dislike documentation (because I have an extremely hard time articulating my thought and solutions); however, because I tend to do a really good job with documentation I tend to get stuck writing the buggers. But as a generalist remark: 'No Developer likes documentation.' For now let's stick with my basic notes and call this post a living document. Here are my notes, fresh, from after watching the new first episode of Merlin second season! Actually, a quick recommendation to anyone who is reading this (if anyone is): I truly recommend you envelope yourself in the medium or task you're trying to tackle. Be one with moment and feel it! For instance: Are you writing a fantasy script / game? What would the music of the genre sound like? For me the Conan the Barbarian soundtrack by Basil Poledouris is frackin awesome. There are many other good CD's out there, which I listen to (some who even use medival instruments, but Conan I keep returning to. It's a creative trigger for me. Ask yourself what would the imagery look like? Time to surf google for artist renditions of fantasy! What would the game feel like? Start playing some of your favorite games that inspire you, be wary though, have some self control and don't let it absorb your time. Anyhow, onto the documentation... Screens, Scenes, and Sprites. Oh My! (groan...) The first thing that came to mind were the screens, I thought the following would suffice: Menu Screen Character Customisation Screen Loading Screen? Battle Ground The Menu Screen Ok. So, the thought here is when the game loads a huge title is displayed: Wizard Wars. The player is prompted with 3 menu items: 1 Player Game, 2 Player Game, and Exit. Since I'm targetting the PC platform, as a non-networked game to start, I picture myself running my mouse over each menu option and the visual element of the menu item changes, along with a sound to indicate that I am over a curent menu item. And as I move my mouse away, it changes back, and possibly an exit mouse sound. Maybe on the screen somewhere is a brazier alit with a magical tome open right beside it, OR, maybe the tome is the menu! I hear the menu music as mellow, not obtrusive or piercing. On a menu item select, a confirmation sound bellows to indicate the players selection. The Esc key will always return me to the previous screens or desktop. The menu screen must feel...dark, like a really important ritual is about to happen and thus the music should build up. 1 Player Game - > Customize Character(s) 2 Player Game - > Customize Character(s) Exit - > Back to Windows Notes: So the first thing I pick up here are a couple things: First and foremost, my artistic abilities suck crap, so I may have to hire an artist (now that i've said that, lets get techy) graphical objects will be positioned within a scene on each screen / window. Menu items will be represented grapically, possibly animated, and have sound / animation effects triggered by user input or a time line. I have an animated scene involving a brazier or fire on a stick IF I was to move this game to the xbox, I'd have to track which menu item is currently selected (unless I do a mouse pointer type thing.) WindowObject has a scene A Scene has many GameObjects GameObject has a position graphic or animation MenuObject is a GameObject which has a mouse in, mouse out, and click event which either does something graphically (animation), does something with sound, or moves to another screen.  Character Customisation Screen With either the 1 or 2 player option selected, both selections will come to this screen; a wizard requires a name, powers, and vestements of course! Player one will configure his character first and then player two. I considered a split screen for PC but to have two people fighting over a keyboard would probably suck. For XBox, a split screen could work; maybe when I get into the networking portion (phase 2 blog?) of this game I will remove the 2 player option for PC and provide only multiplayer and I will leave 2 player for xbox...hmm... Anyhow...I picture the creation process as follows: Name: (textbox / keyboard entry) - for xbox, this would have to be different. Robe Color: (color box, or something) Stats: Speed, Oomph, and Health. (as sliders) 1 as minimum and 10 as maximum. Ok, Back, and Cancel buttons / options. Each stat has a benefit which are listed below. The idea is the player decides if he wants his wizard to run fast, be a tank and ... hit with a purse.Regardless, the player will have a pool of 12 points to use. Ideally, A balanced wizard will have 5 in each attribute. Spells? The only spell of choice is a ball of fire which comes without question. The music and screen should still feel like a ritual. The Character Speed Basically, how fast your character moves and casts. Oomph (Best Monster Truck Voice): PURE POWAH!!! The damage output of your fireball. Health How much damage you can take. Notes: I realise the game dynamics may sound uninteresting at the moment; but I think after a couple releases, we could have some other grand ideas such as: saved profiles, gold to upgrade arsenal of spells, talents, etc...but for now...a vanilla fireball thrower mage will suffice for this experiment. OK. So... a MenuObject  may need to be loosely coupled to allow future items such as networking? may be a button? a CharacterObject has a name speed oomph health and a funky robe color. cap on the three stats (1-10) an arsenal of 1 spell (possibly could expand this) The Loading Screen As is. The Battleground Screen For now, I'm keeping the screen as max resolution for the PC. The screen isn't going to move or even be a split screen. I'm not aiming high here because I want to see what level of change is involved when new features / concepts are added to game content. I'm interested to find out if we could apply techniques such as MVC or MVVM to this type of development or is it too tightly coupled? This reminds me when when my best friend and I were brainstorming our game idea (this is going back a while...1994, 6?) and he cringed at the thought of bringing business technology into games, especially when I suggested a database to store character information and COM / DCOM as the medium, but it seems I wasn't far off (reflecting); just like his implementation of a xml "config file" for dynamic direct-x menus back before .net in 1999...anyhow...i digress... The Battle One screen, two characters lobing balls of fire at each other...It doesn't get better than that. Every so often a scroll appears...and the fireballs bounce off walls, or the wizard has rapid fire, or even scrolls of healing! The scroll options are endless. Two bars at the top, each the color of the wizard (with their name beside the bar) indicate how much health they have. Possibly the appearance of the scrolls means the battle is taking too long? I'm thinking 1 player controls: up, down, left, right and space to fire the button. Or even possibly, mouse click and shift - mouse button to fire a spell in the direction they are facing. Two player controls: a, s, d, f and space AND arrows (up, down, left, right) and Del key or Crtl. The game ends when a player has 0 health and a dialog box appears asking for a rematch / reconfigure / exit. Health goes down when a fireball (friendly or not), connects with a wizard. When a wizard connects with a scroll, a countdown clock / icon appears near the health bar and the wizard begins to glow. For the most part, a wizard can have only scroll 1 effect on him at a time. Notes: Ok, there's alot to cover here. a CharacterObject is a GameObject it travels at a set velocity it travels in a direction it has sounds (walking, running, casting, impact, dying, laughing, whistling, other?) it has animations (walking, running, casting, impact, dying, laughing, idle, other?) it has a lifespan (determined by health) it is alive or dead it has a position a ScrollObject is a GameObject it carries a transferance of points "damage" (or healing, bad scroll effect?) (determinde by caster) it carries a transferance of "other" it is stationary it has a sound on impact it has a stationary animation it has an impact animation / or transfers an impact animation it has a fade animation? it has a lifespan (determined by game) it is alive or dead it has a position a WallObject is a GameObject it has a sound on fireball impact? it is a still image / stationary it has an impact animation / or transfers an impact animation it is dead it has a position A FireBall is a GameObject it carries a transferance of poinst "damage" (or healing, bad scroll effect?) (determinde by caster) it travels at a set velocity it travels in a direction it has a sound it has a travel animation it has an impact animation / or transfers an impact animation it has a fade animation? it has a lifespan (determined by caster) it is alive or dead it has a position As I look at this, I can see some common attributes in each object that I can carry up to the GameObject. I think I'm going to end the documentation here, it's taken me a bit of time to type this all out, tomorrow. I'll load up my IDE and my paint studio to get some good old fashioned cowboy hacking going!   D.

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  • API Message Localization

    - by Jesse Taber
    In my post, “Keep Localizable Strings Close To Your Users” I talked about the internationalization and localization difficulties that can arise when you sprinkle static localizable strings throughout the different logical layers of an application. The main point of that post is that you should have your localizable strings reside as close to the user-facing modules of your application as possible. For example, if you’re developing an ASP .NET web forms application all of the localizable strings should be kept in .resx files that are associated with the .aspx views of the application. In this post I want to talk about how this same concept can be applied when designing and developing APIs. An API Facilitates Machine-to-Machine Interaction You can typically think about a web, desktop, or mobile application as a collection “views” or “screens” through which users interact with the underlying logic and data. The application can be designed based on the assumption that there will be a human being on the other end of the screen working the controls. You are designing a machine-to-person interaction and the application should be built in a way that facilitates the user’s clear understanding of what is going on. Dates should be be formatted in a way that the user will be familiar with, messages should be presented in the user’s preferred language, etc. When building an API, however, there are no screens and you can’t make assumptions about who or what is on the other end of each call. An API is, by definition, a machine-to-machine interaction. A machine-to-machine interaction should be built in a way that facilitates a clear and unambiguous understanding of what is going on. Dates and numbers should be formatted in predictable and standard ways (e.g. ISO 8601 dates) and messages should be presented in machine-parseable formats. For example, consider an API for a time tracking system that exposes a resource for creating a new time entry. The JSON for creating a new time entry for a user might look like: 1: { 2: "userId": 4532, 3: "startDateUtc": "2012-10-22T14:01:54.98432Z", 4: "endDateUtc": "2012-10-22T11:34:45.29321Z" 5: }   Note how the parameters for start and end date are both expressed as ISO 8601 compliant dates in UTC. Using a date format like this in our API leaves little room for ambiguity. It’s also important to note that using ISO 8601 dates is a much, much saner thing than the \/Date(<milliseconds since epoch>)\/ nonsense that is sometimes used in JSON serialization. Probably the most important thing to note about the JSON snippet above is the fact that the end date comes before the start date! The API should recognize that and disallow the time entry from being created, returning an error to the caller. You might inclined to send a response that looks something like this: 1: { 2: "errors": [ {"message" : "The end date must come after the start date"}] 3: }   While this may seem like an appropriate thing to do there are a few problems with this approach: What if there is a user somewhere on the other end of the API call that doesn’t speak English?  What if the message provided here won’t fit properly within the UI of the application that made the API call? What if the verbiage of the message isn’t consistent with the rest of the application that made the API call? What if there is no user directly on the other end of the API call (e.g. this is a batch job uploading time entries once per night unattended)? The API knows nothing about the context from which the call was made. There are steps you could take to given the API some context (e.g.allow the caller to send along a language code indicating the language that the end user speaks), but that will only get you so far. As the designer of the API you could make some assumptions about how the API will be called, but if we start making assumptions we could very easily make the wrong assumptions. In this situation it’s best to make no assumptions and simply design the API in such a way that the caller has the responsibility to convey error messages in a manner that is appropriate for the context in which the error was raised. You would work around some of these problems by allowing callers to add metadata to each request describing the context from which the call is being made (e.g. accepting a ‘locale’ parameter denoting the desired language), but that will add needless clutter and complexity. It’s better to keep the API simple and push those context-specific concerns down to the caller whenever possible. For our very simple time entry example, this can be done by simply changing our error message response to look like this: 1: { 2: "errors": [ {"code": 100}] 3: }   By changing our error error from exposing a string to a numeric code that is easily parseable by another application, we’ve placed all of the responsibility for conveying the actual meaning of the error message on the caller. It’s best to have the caller be responsible for conveying this meaning because the caller understands the context much better than the API does. Now the caller can see error code 100, know that it means that the end date submitted falls before the start date and take appropriate action. Now all of the problems listed out above are non-issues because the caller can simply translate the error code of ‘100’ into the proper action and message for the current context. The numeric code representation of the error is a much better way to facilitate the machine-to-machine interaction that the API is meant to facilitate. An API Does Have Human Users While APIs should be built for machine-to-machine interaction, people still need to wire these interactions together. As a programmer building a client application that will consume the time entry API I would find it frustrating to have to go dig through the API documentation every time I encounter a new error code (assuming the documentation exists and is accurate). The numeric error code approach hurts the discoverability of the API and makes it painful to integrate with. We can help ease this pain by merging our two approaches: 1: { 2: "errors": [ {"code": 100, "message" : "The end date must come after the start date"}] 3: }   Now we have an easily parseable numeric error code for the machine-to-machine interaction that the API is meant to facilitate and a human-readable message for programmers working with the API. The human-readable message here is not intended to be viewed by end-users of the API and as such is not really a “localizable string” in my opinion. We could opt to expose a locale parameter for all API methods and store translations for all error messages, but that’s a lot of extra effort and overhead that doesn’t add a lot real value to the API. I might be a bit of an “ugly American”, but I think it’s probably fine to have the API return English messages when the target for those messages is a programmer. When resources are limited (which they always are), I’d argue that you’re better off hard-coding these messages in English and putting more effort into building more useful features, improving security, tweaking performance, etc.

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  • Table Variables: an empirical approach.

    - by Phil Factor
    It isn’t entirely a pleasant experience to publish an article only to have it described on Twitter as ‘Horrible’, and to have it criticized on the MVP forum. When this happened to me in the aftermath of publishing my article on Temporary tables recently, I was taken aback, because these critics were experts whose views I respect. What was my crime? It was, I think, to suggest that, despite the obvious quirks, it was best to use Table Variables as a first choice, and to use local Temporary Tables if you hit problems due to these quirks, or if you were doing complex joins using a large number of rows. What are these quirks? Well, table variables have advantages if they are used sensibly, but this requires some awareness by the developer about the potential hazards and how to avoid them. You can be hit by a badly-performing join involving a table variable. Table Variables are a compromise, and this compromise doesn’t always work out well. Explicit indexes aren’t allowed on Table Variables, so one cannot use covering indexes or non-unique indexes. The query optimizer has to make assumptions about the data rather than using column distribution statistics when a table variable is involved in a join, because there aren’t any column-based distribution statistics on a table variable. It assumes a reasonably even distribution of data, and is likely to have little idea of the number of rows in the table variables that are involved in queries. However complex the heuristics that are used might be in determining the best way of executing a SQL query, and they most certainly are, the Query Optimizer is likely to fail occasionally with table variables, under certain circumstances, and produce a Query Execution Plan that is frightful. The experienced developer or DBA will be on the lookout for this sort of problem. In this blog, I’ll be expanding on some of the tests I used when writing my article to illustrate the quirks, and include a subsequent example supplied by Kevin Boles. A simplified example. We’ll start out by illustrating a simple example that shows some of these characteristics. We’ll create two tables filled with random numbers and then see how many matches we get between the two tables. We’ll forget indexes altogether for this example, and use heaps. We’ll try the same Join with two table variables, two table variables with OPTION (RECOMPILE) in the JOIN clause, and with two temporary tables. It is all a bit jerky because of the granularity of the timing that isn’t actually happening at the millisecond level (I used DATETIME). However, you’ll see that the table variable is outperforming the local temporary table up to 10,000 rows. Actually, even without a use of the OPTION (RECOMPILE) hint, it is doing well. What happens when your table size increases? The table variable is, from around 30,000 rows, locked into a very bad execution plan unless you use OPTION (RECOMPILE) to provide the Query Analyser with a decent estimation of the size of the table. However, if it has the OPTION (RECOMPILE), then it is smokin’. Well, up to 120,000 rows, at least. It is performing better than a Temporary table, and in a good linear fashion. What about mixed table joins, where you are joining a temporary table to a table variable? You’d probably expect that the query analyzer would throw up its hands and produce a bad execution plan as if it were a table variable. After all, it knows nothing about the statistics in one of the tables so how could it do any better? Well, it behaves as if it were doing a recompile. And an explicit recompile adds no value at all. (we just go up to 45000 rows since we know the bigger picture now)   Now, if you were new to this, you might be tempted to start drawing conclusions. Beware! We’re dealing with a very complex beast: the Query Optimizer. It can come up with surprises What if we change the query very slightly to insert the results into a Table Variable? We change nothing else and just measure the execution time of the statement as before. Suddenly, the table variable isn’t looking so much better, even taking into account the time involved in doing the table insert. OK, if you haven’t used OPTION (RECOMPILE) then you’re toast. Otherwise, there isn’t much in it between the Table variable and the temporary table. The table variable is faster up to 8000 rows and then not much in it up to 100,000 rows. Past the 8000 row mark, we’ve lost the advantage of the table variable’s speed. Any general rule you may be formulating has just gone for a walk. What we can conclude from this experiment is that if you join two table variables, and can’t use constraints, you’re going to need that Option (RECOMPILE) hint. Count Dracula and the Horror Join. These tables of integers provide a rather unreal example, so let’s try a rather different example, and get stuck into some implicit indexing, by using constraints. What unusual words are contained in the book ‘Dracula’ by Bram Stoker? Here we get a table of all the common words in the English language (60,387 of them) and put them in a table. We put them in a Table Variable with the word as a primary key, a Table Variable Heap and a Table Variable with a primary key. We then take all the distinct words used in the book ‘Dracula’ (7,558 of them). We then create a table variable and insert into it all those uncommon words that are in ‘Dracula’. i.e. all the words in Dracula that aren’t matched in the list of common words. To do this we use a left outer join, where the right-hand value is null. The results show a huge variation, between the sublime and the gorblimey. If both tables contain a Primary Key on the columns we join on, and both are Table Variables, it took 33 Ms. If one table contains a Primary Key, and the other is a heap, and both are Table Variables, it took 46 Ms. If both Table Variables use a unique constraint, then the query takes 36 Ms. If neither table contains a Primary Key and both are Table Variables, it took 116383 Ms. Yes, nearly two minutes!! If both tables contain a Primary Key, one is a Table Variables and the other is a temporary table, it took 113 Ms. If one table contains a Primary Key, and both are Temporary Tables, it took 56 Ms.If both tables are temporary tables and both have primary keys, it took 46 Ms. Here we see table variables which are joined on their primary key again enjoying a  slight performance advantage over temporary tables. Where both tables are table variables and both are heaps, the query suddenly takes nearly two minutes! So what if you have two heaps and you use option Recompile? If you take the rogue query and add the hint, then suddenly, the query drops its time down to 76 Ms. If you add unique indexes, then you've done even better, down to half that time. Here are the text execution plans.So where have we got to? Without drilling down into the minutiae of the execution plans we can begin to create a hypothesis. If you are using table variables, and your tables are relatively small, they are faster than temporary tables, but as the number of rows increases you need to do one of two things: either you need to have a primary key on the column you are using to join on, or else you need to use option (RECOMPILE) If you try to execute a query that is a join, and both tables are table variable heaps, you are asking for trouble, well- slow queries, unless you give the table hint once the number of rows has risen past a point (30,000 in our first example, but this varies considerably according to context). Kevin’s Skew In describing the table-size, I used the term ‘relatively small’. Kevin Boles produced an interesting case where a single-row table variable produces a very poor execution plan when joined to a very, very skewed table. In the original, pasted into my article as a comment, a column consisted of 100000 rows in which the key column was one number (1) . To this was added eight rows with sequential numbers up to 9. When this was joined to a single-tow Table Variable with a key of 2 it produced a bad plan. This problem is unlikely to occur in real usage, and the Query Optimiser team probably never set up a test for it. Actually, the skew can be slightly less extreme than Kevin made it. The following test showed that once the table had 54 sequential rows in the table, then it adopted exactly the same execution plan as for the temporary table and then all was well. Undeniably, real data does occasionally cause problems to the performance of joins in Table Variables due to the extreme skew of the distribution. We've all experienced Perfectly Poisonous Table Variables in real live data. As in Kevin’s example, indexes merely make matters worse, and the OPTION (RECOMPILE) trick does nothing to help. In this case, there is no option but to use a temporary table. However, one has to note that once the slight de-skew had taken place, then the plans were identical across a huge range. Conclusions Where you need to hold intermediate results as part of a process, Table Variables offer a good alternative to temporary tables when used wisely. They can perform faster than a temporary table when the number of rows is not great. For some processing with huge tables, they can perform well when only a clustered index is required, and when the nature of the processing makes an index seek very effective. Table Variables are scoped to the batch or procedure and are unlikely to hang about in the TempDB when they are no longer required. They require no explicit cleanup. Where the number of rows in the table is moderate, you can even use them in joins as ‘Heaps’, unindexed. Beware, however, since, as the number of rows increase, joins on Table Variable heaps can easily become saddled by very poor execution plans, and this must be cured either by adding constraints (UNIQUE or PRIMARY KEY) or by adding the OPTION (RECOMPILE) hint if this is impossible. Occasionally, the way that the data is distributed prevents the efficient use of Table Variables, and this will require using a temporary table instead. Tables Variables require some awareness by the developer about the potential hazards and how to avoid them. If you are not prepared to do any performance monitoring of your code or fine-tuning, and just want to pummel out stuff that ‘just runs’ without considering namby-pamby stuff such as indexes, then stick to Temporary tables. If you are likely to slosh about large numbers of rows in temporary tables without considering the niceties of processing just what is required and no more, then temporary tables provide a safer and less fragile means-to-an-end for you.

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  • Who writes the words? A rant with graphs.

    - by Roger Hart
    If you read my rant, you'll know that I'm getting a bit of a bee in my bonnet about user interface text. But rather than just yelling about the way the world should be (short version: no UI text would suck), it seemed prudent to actually gather some data. Rachel Potts has made an excellent first foray, by conducting a series of interviews across organizations about how they write user interface text. You can read Rachel's write up here. She presents the facts as she found them, and doesn't editorialise. The result is insightful, but impartial isn't really my style. So here's a rant with graphs. My method, and how it sucked I sent out a short survey. Survey design is one of my hobby-horses, and since some smartarse in the comments will mention it if I don't, I'll step up and confess: I did not design this one well. It was potentially ambiguous, implicitly excluded people, and since I only really advertised it on Twitter and a couple of mailing lists the sample will be chock full of biases. Regardless, these were the questions: What do you do? Select the option that best describes your role What kind of software does your organization make? (optional) In your organization, who writes the text on your software user interfaces? (for example: button names, static text, tooltips, and so on) Tick all that apply. In your organization who is responsible for user interface text? Who "owns" it? The most glaring issue (apart from question 3 being a bit broken) was that I didn't make it clear that I was asking about applications. Desktop, mobile, or web, I wouldn't have minded. In fact, it might have been interesting to categorize and compare. But a few respondents commented on the seeming lack of relevance, since they didn't really make software. There were some other issues too. It wasn't the best survey. So, you know, pinch of salt time with what follows. Despite this, there were 100 or so respondents. This post covers the overview, and you can look at the raw data in this spreadsheet What did people do? Boring graph number one: I wasn't expecting that. Given I pimped the survey on twitter and a couple of Tech Comms discussion lists, I was more banking on and even Content Strategy/Tech Comms split. What the "Others" specified: Three people chipped in with Technical Writer. Author, apparently, doesn't cut it. There's a "nobody reads the instructions" joke in there somewhere, I'm sure. There were a couple of hybrid roles, including Tech Comms and Testing, which sounds gruelling and thankless. There was also, an Intranet Manager, a Creative Director, a Consultant, a CTO, an Information Architect, and a Translator. That's a pretty healthy slice through the industry. Who wrote UI text? Boring graph number two: Annoyingly, I made this a "tick all that apply" question, so I can't make crude and inflammatory generalizations about percentages. This is more about who gets involved in user interface wording. So don't panic about the number of developers writing UI text. First off, it just means they're involved. Second, they might be good at it. What? It could happen. Ours are involved - they write a placeholder and flag it to me for changes. Sometimes I don't make any. It's also not surprising that there's so much UX in the mix. Some of that will be people taking care, and crafting an understandable interface. Some of it will be whatever text goes on the wireframe making it into production. I'm going to assume that's what happened at eBay, when their iPhone app purportedly shipped with the placeholder text "Some crappy content goes here". Ahem. Listing all 17 "other" responses would make this post lengthy indeed, but you can read them in the raw data spreadsheet. The award for the approach that sounds the most like a good idea yet carries the highest risk of ending badly goes to whoever offered up "External agencies using focus groups". If you're reading this, and that actually works, leave a comment. I'm fascinated. Who owned UI text Stop. Bar chart time: Wow. Let's cut to the chase, and by "chase", I mean those inflammatory generalizations I was talking about: In around 60% of cases the person responsible for user interface text probably lacks the relevant expertise. Even in the categories I count as being likely to have relevant skills (Marketing Copywriters, Content Strategists, Technical Authors, and User Experience Designers) there's a case for each role being unsuited, as you'll see in Rachel's blog post So it's not as simple as my headline. Does that mean that you personally, Mr Developer reading this, write bad button names? Of course not. I know nothing about you. It rather implies that as a category, the majority of people looking after UI text have neither communication nor user experience as their primary skill set, and as such will probably only be good at this by happy accident. I don't have a way of measuring those frequency of those accidents. What the Others specified: I don't know who owns it. I assume the project manager is responsible. "copywriters" when they wish to annoy me. the client's web maintenance person, often PR or MarComm That last one chills me to the bone. Still, at least nobody said "the work experience kid". You can see the rest in the spreadsheet. My overwhelming impression here is of user interface text as an unloved afterthought. There were fewer "nobody" responses than I expected, and a much broader split. But the relative predominance of developers owning and writing UI text suggests to me that organizations don't see it as something worth dedicating attention to. If true, that's bothersome. Because the words on the screen, particularly the names of things, are fundamental to the ability to understand an use software. It's also fascinating that Technical Authors and Content Strategists are neck and neck. For such a nascent discipline, Content Strategy appears to have made a mark on software development. Or my sample is skewed. But it feels like a bit of validation for my rant: Content Strategy is eating Tech Comms' lunch. That's not a bad thing. Well, not if the UI text is getting done well. And that's the caveat to this whole post. I couldn't care less who writes UI text, provided they consider the user and don't suck at it. I care that it may be falling by default to people poorly disposed to doing it right. And I care about that because so much user interface text sucks. The most interesting question Was one I forgot to ask. It's this: Does your organization have technical authors/writers? Like a lot of survey data, that doesn't tell you much on its own. But once we get a bit dimensional, it become more interesting. So taken with the other questions, this would have let me find out what I really want to know: What proportion of organizations have Tech Comms professionals but don't use them for UI text? Who writes UI text in their place? Why this happens? It's possible (feasible is another matter) that hundreds of companies have tech authors who don't work on user interfaces because they've empirically discovered that someone else, say the Marketing Copywriter, is better at it. And once we've all finished laughing, I'll point out that I've met plenty of tech authors who just aren't used to thinking about users at the point of need in the way UI text and embedded user assistance require. If you've got what I regard, perhaps unfairly, as the bad kind of tech author - the old-school kind with the thousand-page pdf and the grammar obsession - if you've got one of those then you probably are better off getting the UX folk or the copywriters to do your UI text. At the very least, they'll derive terminology from user research.

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  • Source-control 'wet-work'?

    - by Phil Factor
    When a design or creative work is flawed beyond remedy, it is often best to destroy it and start again. The other day, I lost the code to a long and intricate SQL batch I was working on. I’d thought it was impossible, but it happened. With all the technology around that is designed to prevent this occurring, this sort of accident has become a rare event.  If it weren’t for a deranged laptop, and my distraction, the code wouldn’t have been lost this time.  As always, I sighed, had a soothing cup of tea, and typed it all in again.  The new code I hastily tapped in  was much better: I’d held in my head the essence of how the code should work rather than the details: I now knew for certain  the start point, the end, and how it should be achieved. Instantly the detritus of half-baked thoughts fell away and I was able to write logical code that performed better.  Because I could work so quickly, I was able to hold the details of all the columns and variables in my head, and the dynamics of the flow of data. It was, in fact, easier and quicker to start from scratch rather than tidy up and refactor the existing code with its inevitable fumbling and half-baked ideas. What a shame that technology is now so good that developers rarely experience the cleansing shock of losing one’s code and having to rewrite it from scratch.  If you’ve never accidentally lost  your code, then it is worth doing it deliberately once for the experience. Creative people have, until Technology mistakenly prevented it, torn up their drafts or sketches, threw them in the bin, and started again from scratch.  Leonardo’s obsessive reworking of the Mona Lisa was renowned because it was so unusual:  Most artists have been utterly ruthless in destroying work that didn’t quite make it. Authors are particularly keen on writing afresh, and the results are generally positive. Lawrence of Arabia actually lost the entire 250,000 word manuscript of ‘The Seven Pillars of Wisdom’ by accidentally leaving it on a train at Reading station, before rewriting a much better version.  Now, any writer or artist is seduced by technology into altering or refining their work rather than casting it dramatically in the bin or setting a light to it on a bonfire, and rewriting it from the blank page.  It is easy to pick away at a flawed work, but the real creative process is far more brutal. Once, many years ago whilst running a software house that supplied commercial software to local businesses, I’d been supervising an accounting system for a farming cooperative. No packaged system met their needs, and it was all hand-cut code.  For us, it represented a breakthrough as it was for a government organisation, and success would guarantee more contracts. As you’ve probably guessed, the code got mangled in a disk crash just a week before the deadline for delivery, and the many backups all proved to be entirely corrupted by a faulty tape drive.  There were some fragments left on individual machines, but they were all of different versions.  The developers were in despair.  Strangely, I managed to re-write the bulk of a three-month project in a manic and caffeine-soaked weekend.  Sure, that elegant universally-applicable input-form routine was‘nt quite so elegant, but it didn’t really need to be as we knew what forms it needed to support.  Yes, the code lacked architectural elegance and reusability. By dawn on Monday, the application passed its integration tests. The developers rose to the occasion after I’d collapsed, and tidied up what I’d done, though they were reproachful that some of the style and elegance had gone out of the application. By the delivery date, we were able to install it. It was a smaller, faster application than the beta they’d seen and the user-interface had a new, rather Spartan, appearance that we swore was done to conform to the latest in user-interface guidelines. (we switched to Helvetica font to look more ‘Bauhaus’ ). The client was so delighted that he forgave the new bugs that had crept in. I still have the disk that crashed, up in the attic. In IT, we have had mixed experiences from complete re-writes. Lotus 123 never really recovered from a complete rewrite from assembler into C, Borland made the mistake with Arago and Quattro Pro  and Netscape’s complete rewrite of their Navigator 4 browser was a white-knuckle ride. In all cases, the decision to rewrite was a result of extreme circumstances where no other course of action seemed possible.   The rewrite didn’t come out of the blue. I prefer to remember the rewrite of Minix by young Linus Torvalds, or the rewrite of Bitkeeper by a slightly older Linus.  The rewrite of CP/M didn’t do too badly either, did it? Come to think of it, the guy who decided to rewrite the windowing system of the Xerox Star never regretted the decision. I’ll agree that one should often resist calls for a rewrite. One of the worst habits of the more inexperienced programmer is to denigrate whatever code he or she inherits, and then call loudly for a complete rewrite. They are buoyed up by the mistaken belief that they can do better. This, however, is a different psychological phenomenon, more related to the idea of some motorcyclists that they are operating on infinite lives, or the occasional squaddies that if they charge the machine-guns determinedly enough all will be well. Grim experience brings out the humility in any experienced programmer.  I’m referring to quite different circumstances here. Where a team knows the requirements perfectly, are of one mind on methodology and coding standards, and they already have a solution, then what is wrong with considering  a complete rewrite? Rewrites are so painful in the early stages, until that point where one realises the payoff, that even I quail at the thought. One needs a natural disaster to push one over the edge. The trouble is that source-control systems, and disaster recovery systems, are just too good nowadays.   If I were to lose this draft of this very blog post, I know I’d rewrite it much better. However, if you read this, you’ll know I didn’t have the nerve to delete it and start again.  There was a time that one prayed that unreliable hardware would deliver you from an unmaintainable mess of a codebase, but now technology has made us almost entirely immune to such a merciful act of God. An old friend of mine with long experience in the software industry has long had the idea of the ‘source-control wet-work’,  where one hires a malicious hacker in some wild eastern country to hack into one’s own  source control system to destroy all trace of the source to an application. Alas, backup systems are just too good to make this any more than a pipedream. Somehow, it would be difficult to promote the idea. As an alternative, could one construct a source control system that, on doing all the code-quality metrics, would systematically destroy all trace of source code that failed the quality test? Alas, I can’t see many managers buying into the idea. In reading the full story of the near-loss of Toy Story 2, it set me thinking. It turned out that the lucky restoration of the code wasn’t the happy ending one first imagined it to be, because they eventually came to the conclusion that the plot was fundamentally flawed and it all had to be rewritten anyway.  Was this an early  case of the ‘source-control wet-job’?’ It is very hard nowadays to do a rapid U-turn in a development project because we are far too prone to cling to our existing source-code.

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  • Source-control 'wet-work'?

    - by Phil Factor
    When a design or creative work is flawed beyond remedy, it is often best to destroy it and start again. The other day, I lost the code to a long and intricate SQL batch I was working on. I’d thought it was impossible, but it happened. With all the technology around that is designed to prevent this occurring, this sort of accident has become a rare event.  If it weren’t for a deranged laptop, and my distraction, the code wouldn’t have been lost this time.  As always, I sighed, had a soothing cup of tea, and typed it all in again.  The new code I hastily tapped in  was much better: I’d held in my head the essence of how the code should work rather than the details: I now knew for certain  the start point, the end, and how it should be achieved. Instantly the detritus of half-baked thoughts fell away and I was able to write logical code that performed better.  Because I could work so quickly, I was able to hold the details of all the columns and variables in my head, and the dynamics of the flow of data. It was, in fact, easier and quicker to start from scratch rather than tidy up and refactor the existing code with its inevitable fumbling and half-baked ideas. What a shame that technology is now so good that developers rarely experience the cleansing shock of losing one’s code and having to rewrite it from scratch.  If you’ve never accidentally lost  your code, then it is worth doing it deliberately once for the experience. Creative people have, until Technology mistakenly prevented it, torn up their drafts or sketches, threw them in the bin, and started again from scratch.  Leonardo’s obsessive reworking of the Mona Lisa was renowned because it was so unusual:  Most artists have been utterly ruthless in destroying work that didn’t quite make it. Authors are particularly keen on writing afresh, and the results are generally positive. Lawrence of Arabia actually lost the entire 250,000 word manuscript of ‘The Seven Pillars of Wisdom’ by accidentally leaving it on a train at Reading station, before rewriting a much better version.  Now, any writer or artist is seduced by technology into altering or refining their work rather than casting it dramatically in the bin or setting a light to it on a bonfire, and rewriting it from the blank page.  It is easy to pick away at a flawed work, but the real creative process is far more brutal. Once, many years ago whilst running a software house that supplied commercial software to local businesses, I’d been supervising an accounting system for a farming cooperative. No packaged system met their needs, and it was all hand-cut code.  For us, it represented a breakthrough as it was for a government organisation, and success would guarantee more contracts. As you’ve probably guessed, the code got mangled in a disk crash just a week before the deadline for delivery, and the many backups all proved to be entirely corrupted by a faulty tape drive.  There were some fragments left on individual machines, but they were all of different versions.  The developers were in despair.  Strangely, I managed to re-write the bulk of a three-month project in a manic and caffeine-soaked weekend.  Sure, that elegant universally-applicable input-form routine was‘nt quite so elegant, but it didn’t really need to be as we knew what forms it needed to support.  Yes, the code lacked architectural elegance and reusability. By dawn on Monday, the application passed its integration tests. The developers rose to the occasion after I’d collapsed, and tidied up what I’d done, though they were reproachful that some of the style and elegance had gone out of the application. By the delivery date, we were able to install it. It was a smaller, faster application than the beta they’d seen and the user-interface had a new, rather Spartan, appearance that we swore was done to conform to the latest in user-interface guidelines. (we switched to Helvetica font to look more ‘Bauhaus’ ). The client was so delighted that he forgave the new bugs that had crept in. I still have the disk that crashed, up in the attic. In IT, we have had mixed experiences from complete re-writes. Lotus 123 never really recovered from a complete rewrite from assembler into C, Borland made the mistake with Arago and Quattro Pro  and Netscape’s complete rewrite of their Navigator 4 browser was a white-knuckle ride. In all cases, the decision to rewrite was a result of extreme circumstances where no other course of action seemed possible.   The rewrite didn’t come out of the blue. I prefer to remember the rewrite of Minix by young Linus Torvalds, or the rewrite of Bitkeeper by a slightly older Linus.  The rewrite of CP/M didn’t do too badly either, did it? Come to think of it, the guy who decided to rewrite the windowing system of the Xerox Star never regretted the decision. I’ll agree that one should often resist calls for a rewrite. One of the worst habits of the more inexperienced programmer is to denigrate whatever code he or she inherits, and then call loudly for a complete rewrite. They are buoyed up by the mistaken belief that they can do better. This, however, is a different psychological phenomenon, more related to the idea of some motorcyclists that they are operating on infinite lives, or the occasional squaddies that if they charge the machine-guns determinedly enough all will be well. Grim experience brings out the humility in any experienced programmer.  I’m referring to quite different circumstances here. Where a team knows the requirements perfectly, are of one mind on methodology and coding standards, and they already have a solution, then what is wrong with considering  a complete rewrite? Rewrites are so painful in the early stages, until that point where one realises the payoff, that even I quail at the thought. One needs a natural disaster to push one over the edge. The trouble is that source-control systems, and disaster recovery systems, are just too good nowadays.   If I were to lose this draft of this very blog post, I know I’d rewrite it much better. However, if you read this, you’ll know I didn’t have the nerve to delete it and start again.  There was a time that one prayed that unreliable hardware would deliver you from an unmaintainable mess of a codebase, but now technology has made us almost entirely immune to such a merciful act of God. An old friend of mine with long experience in the software industry has long had the idea of the ‘source-control wet-work’,  where one hires a malicious hacker in some wild eastern country to hack into one’s own  source control system to destroy all trace of the source to an application. Alas, backup systems are just too good to make this any more than a pipedream. Somehow, it would be difficult to promote the idea. As an alternative, could one construct a source control system that, on doing all the code-quality metrics, would systematically destroy all trace of source code that failed the quality test? Alas, I can’t see many managers buying into the idea. In reading the full story of the near-loss of Toy Story 2, it set me thinking. It turned out that the lucky restoration of the code wasn’t the happy ending one first imagined it to be, because they eventually came to the conclusion that the plot was fundamentally flawed and it all had to be rewritten anyway.  Was this an early  case of the ‘source-control wet-job’?’ It is very hard nowadays to do a rapid U-turn in a development project because we are far too prone to cling to our existing source-code.

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  • Super constructor must be a first statement in Java constructor [closed]

    - by Val
    I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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  • Developer’s Life – Every Developer is a Batman

    - by Pinal Dave
    Batman is one of the darkest superheroes in the fantasy canon.  He does not come to his powers through any sort of magical coincidence or radioactive insect, but through a lot of psychological scarring caused by witnessing the death of his parents.  Despite his dark back story, he possesses a lot of admirable abilities that I feel bear comparison to developers. Batman has the distinct advantage that his alter ego, Bruce Wayne is a millionaire (or billionaire in today’s reboots).  This means that he can spend his time working on his athletic abilities, building a secret lair, and investing his money in cool tools.  This might not be true for developers (well, most developers), but I still think there are many parallels. So how are developers like Batman? Well, read on my list of reasons. Develop Skills Batman works on his skills.  He didn’t get the strength to scale Gotham’s skyscrapers by inheriting his powers or suffering an industrial accident.  Developers also hone their skills daily.  They might not be doing pull-ups and scaling buldings, but I think their skills are just as impressive. Clear Goals Batman is driven to build a better Gotham.  He knows that the criminal who killed his parents was a small-time thief, not a super villain – so he has larger goals in mind than simply chasing one villain.  He wants his city as a whole to be better.  Developers are also driven to make things better.  It can be easy to get hung up on one problem, but in the end it is best to focus on the well-being of the system as a whole. Ultimate Teamplayers Batman is the hero Gotham needs – even when that means appearing to be the bad guys.  Developers probably know that feeling well.  Batman takes the fall for a crime he didn’t commit, and developers often have to deliver bad news about the limitations of their networks and servers.  It’s not always a job filled with glory and thanks, but someone has to do it. Always Ready Batman and the Boy Scouts have this in common – they are always prepared.  Let’s add developers to this list.  Batman has an amazing tool belt with gadgets and gizmos, and let’s not even get into all the functions of the Batmobile!  Developers’ skills might be the knowledge and skills they have developed, not tools they can carry in a utility belt, but that doesn’t make them any less impressive. 100% Dedication Bruce Wayne cultivates the personality of a playboy, never keeping the same girlfriend for long and spending his time partying.  Even though he hides it, his driving force is his deep concern and love for his friends and the city as a whole.  Developers also care a lot about their company and employees – even when it is driving them crazy.  You do your best work when you care about your job on a personal level. Quality Output Batman believes the city deserves to be saved.  The citizens might have a love-hate relationship with both Batman and Bruce Wayne, and employees might not always appreciate developers.  Batman and developers, though, keep working for the best of everyone. I hope you are all enjoying reading about developers-as-superheroes as much as I am enjoying writing about them.  Please tell me how else developers are like Superheroes in the comments – especially if you know any developers who are faster than a speeding bullet and can leap tall buildings in a single bound. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Developer, Superhero

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  • Windows Phone 7 Prototype 001: Speech Recognition on WP7

    At some point in the future it will be awesome when you can just tell your computer what to do and it does it - without typing to help those of us with a blistering 11 WPM hunk and peck technique. Siri, a mobile digital assistant using speech recognition was voted best tech at SXSW. I dont know about that one. Although, I'm sure it will get better when Apple rebuilds it and  bundles on iPhone 5. So how would you do that on WP7? There have been some videos floating around showing Bing with some voice control so obviously the phone has speech recognition. So what options are there: System.Speech? Not included in WP7/SL Nuance software like Siri? No WP7/SL version yet. Invoking the SAPI dlls on the phone? No automation factory in WP7 SL. Web services using System.Speech and mic on the phone? YES! The last one was my least favorite but that works for now. I built a quick sample app to show how to do text-to-speech and speech recognition on WP7.   @eklimczak will not be happy with the developer designed UI. In this sample there is web service with provides access to the system.speech APIs in .NET. Basically its just passing around byte arrays. On the phone its using the XNA audio frameworks to play the text-to-speech stream and to record using the microphone. The code is pretty simple and you can download from the link at the end of this post. The only things to note are adjusting the WCF config to handle larger byte uploads and the Microphone API is a little weird with that 1 second buffer. It would be nice if you could just to mic.start and mic.end which would return an array of bytes instead of managing your own stream inside the buffer ready callback. Couple of downsides to this approach: Recoding from the phone has some static. Could be my code or the my mic is bad / not calibrated right. Having to make web service calls instead of local access is not ideal (Microsoft, please add an API for the SAPI dlls) Although in the context of an app like Siri its not so bad since you need to do web service lookups to get data back Speech recognition quality really depends on either a) a limited grammar set like that pizza grammar in the sample or b) training the recognizer. For the latter it would be annoying to have users train the system. Using the System.Speech stuff youd have to have a profile for each user. So until Microsoft adds some speech client APIs on the phone or Nuance releases a wp7 product, this is a decent workaround. In the future Id like to build something similar to Siri. I shall call it Iris in homage. Im a big fan of mobile speech apps because frankly its just not safe to Google while driving. Since some of my designer co-workers have been posting UI sketches for WP7, Id like to start posting some code prototypes for things I try out on the phone. That will probably last 2 weeks, but for the moment I have like 10 posts in the queue. Sample Code 100% guaranteed to work on my emulatorDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • More SQL Smells

    - by Nick Harrison
    Let's continue exploring some of the SQL Smells from Phil's list. He has been putting together. Datatype mis-matches in predicates that rely on implicit conversion.(Plamen Ratchev) This is a great example poking holes in the whole theory of "If it works it's not broken" Queries will this probably will generally work and give the correct response. In fact, without careful analysis, you probably may be completely oblivious that there is even a problem. This subtle little problem will needlessly complicate queries and slow them down regardless of the indexes applied. Consider this example: CREATE TABLE [dbo].[Page](     [PageId] [int] IDENTITY(1,1) NOT NULL,     [Title] [varchar](75) NOT NULL,     [Sequence] [int] NOT NULL,     [ThemeId] [int] NOT NULL,     [CustomCss] [text] NOT NULL,     [CustomScript] [text] NOT NULL,     [PageGroupId] [int] NOT NULL;  CREATE PROCEDURE PageSelectBySequence ( @sequenceMin smallint , @sequenceMax smallint ) AS BEGIN SELECT [PageId] , [Title] , [Sequence] , [ThemeId] , [CustomCss] , [CustomScript] , [PageGroupId] FROM [CMS].[dbo].[Page] WHERE Sequence BETWEEN @sequenceMin AND @SequenceMax END  Note that the Sequence column is defined as int while the sequence parameter is defined as a small int. The problem is that the database may have to do a lot of type conversions to evaluate the query. In some cases, this may even negate the indexes that you have in place. Using Correlated subqueries instead of a join   (Dave_Levy/ Plamen Ratchev) There are two main problems here. The first is a little subjective, since this is a non-standard way of expressing the query, it is harder to understand. The other problem is much more objective and potentially problematic. You are taking much of the control away from the optimizer. Written properly, such a query may well out perform a corresponding query written with traditional joins. More likely than not, performance will degrade. Whenever you assume that you know better than the optimizer, you will most likely be wrong. This is the fundmental problem with any hint. Consider a query like this:  SELECT Page.Title , Page.Sequence , Page.ThemeId , Page.CustomCss , Page.CustomScript , PageEffectParams.Name , PageEffectParams.Value , ( SELECT EffectName FROM dbo.Effect WHERE EffectId = dbo.PageEffects.EffectId ) AS EffectName FROM Page INNER JOIN PageEffect ON Page.PageId = PageEffects.PageId INNER JOIN PageEffectParam ON PageEffects.PageEffectId = PageEffectParams.PageEffectId  This can and should be written as:  SELECT Page.Title , Page.Sequence , Page.ThemeId , Page.CustomCss , Page.CustomScript , PageEffectParams.Name , PageEffectParams.Value , EffectName FROM Page INNER JOIN PageEffect ON Page.PageId = PageEffects.PageId INNER JOIN PageEffectParam ON PageEffects.PageEffectId = PageEffectParams.PageEffectId INNER JOIN dbo.Effect ON dbo.Effects.EffectId = dbo.PageEffects.EffectId  The correlated query may just as easily show up in the where clause. It's not a good idea in the select clause or the where clause. Few or No comments. This one is a bit more complicated and controversial. All comments are not created equal. Some comments are helpful and need to be included. Other comments are not necessary and may indicate a problem. I tend to follow the rule of thumb that comments that explain why are good. Comments that explain how are bad. Many people may be shocked to hear the idea of a bad comment, but hear me out. If a comment is needed to explain what is going on or how it works, the logic is too complex and needs to be simplified. Comments that explain why are good. Comments may explain why the sql is needed are good. Comments that explain where the sql is used are good. Comments that explain how tables are related should not be needed if the sql is well written. If they are needed, you need to consider reworking the sql or simplify your data model. Use of functions in a WHERE clause. (Anil Das) Calling a function in the where clause will often negate the indexing strategy. The function will be called for every record considered. This will often a force a full table scan on the tables affected. Calling a function will not guarantee that there is a full table scan, but there is a good chance that it will. If you find that you often need to write queries using a particular function, you may need to add a column to the table that has the function already applied.

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  • Reconciling the Boy Scout Rule and Opportunistic Refactoring with code reviews

    - by t0x1n
    I am a great believer in the Boy Scout Rule: Always check a module in cleaner than when you checked it out." No matter who the original author was, what if we always made some effort, no matter how small, to improve the module. What would be the result? I think if we all followed that simple rule, we'd see the end of the relentless deterioration of our software systems. Instead, our systems would gradually get better and better as they evolved. We'd also see teams caring for the system as a whole, rather than just individuals caring for their own small little part. I am also a great believer in the related idea of Opportunistic Refactoring: Although there are places for some scheduled refactoring efforts, I prefer to encourage refactoring as an opportunistic activity, done whenever and wherever code needs to cleaned up - by whoever. What this means is that at any time someone sees some code that isn't as clear as it should be, they should take the opportunity to fix it right there and then - or at least within a few minutes Particularly note the following excerpt from the refactoring article: I'm wary of any development practices that cause friction for opportunistic refactoring ... My sense is that most teams don't do enough refactoring, so it's important to pay attention to anything that is discouraging people from doing it. To help flush this out be aware of any time you feel discouraged from doing a small refactoring, one that you're sure will only take a minute or two. Any such barrier is a smell that should prompt a conversation. So make a note of the discouragement and bring it up with the team. At the very least it should be discussed during your next retrospective. Where I work, there is one development practice that causes heavy friction - Code Review (CR). Whenever I change anything that's not in the scope of my "assignment" I'm being rebuked by my reviewers that I'm making the change harder to review. This is especially true when refactoring is involved, since it makes "line by line" diff comparison difficult. This approach is the standard here, which means opportunistic refactoring is seldom done, and only "planned" refactoring (which is usually too little, too late) takes place, if at all. I claim that the benefits are worth it, and that 3 reviewers will work a little harder (to actually understand the code before and after, rather than look at the narrow scope of which lines changed - the review itself would be better due to that alone) so that the next 100 developers reading and maintaining the code will benefit. When I present this argument my reviewers, they say they have no problem with my refactoring, as long as it's not in the same CR. However I claim this is a myth: (1) Most of the times you only realize what and how you want to refactor when you're in the midst of your assignment. As Martin Fowler puts it: As you add the functionality, you realize that some code you're adding contains some duplication with some existing code, so you need to refactor the existing code to clean things up... You may get something working, but realize that it would be better if the interaction with existing classes was changed. Take that opportunity to do that before you consider yourself done. (2) Nobody is going to look favorably at you releasing "refactoring" CRs you were not supposed to do. A CR has a certain overhead and your manager doesn't want you to "waste your time" on refactoring. When it's bundled with the change you're supposed to do, this issue is minimized. The issue is exacerbated by Resharper, as each new file I add to the change (and I can't know in advance exactly which files would end up changed) is usually littered with errors and suggestions - most of which are spot on and totally deserve fixing. The end result is that I see horrible code, and I just leave it there. Ironically, I feel that fixing such code not only will not improve my standings, but actually lower them and paint me as the "unfocused" guy who wastes time fixing things nobody cares about instead of doing his job. I feel bad about it because I truly despise bad code and can't stand watching it, let alone call it from my methods! Any thoughts on how I can remedy this situation ?

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  • Tuning Red Gate: #3 of Lots

    - by Grant Fritchey
    I'm drilling down into the metrics about SQL Server itself available to me in the Analysis tab of SQL Monitor to see what's up with our two problematic servers. In the previous post I'd noticed that rg-sql01 had quite a few CPU spikes. So one of the first things I want to check there is how much CPU is getting used by SQL Server itself. It's possible we're looking at some other process using up all the CPU Nope, It's SQL Server. I compared this to the rg-sql02 server: You can see that there is a more, consistently low set of CPU counters there. I clearly need to look at rg-sql01 and capture more specific data around the queries running on it to identify which ones are causing these CPU spikes. I always like to look at the Batch Requests/sec on a server, not because it's an indication of a problem, but because it gives you some idea of the load. Just how much is this server getting hit? Here are rg-sql01 and rg-sql02: Of the two, clearly rg-sql01 has a lot of activity. Remember though, that's all this is a measure of, activity. It doesn't suggest anything other than what it says, the number of requests coming in. But it's the kind of thing you want to know in order to understand how the system is used. Are you seeing a correlation between the number of requests and the CPU usage, or a reverse correlation, the number of requests drops as the CPU spikes? See, it's useful. Some of the details you can look at are Compilations/sec, Compilations/Batch and Recompilations/sec. These give you some idea of how the cache is getting used within the system. None of these showed anything interesting on either server. One metric that I like (even though I know it can be controversial) is the Page Life Expectancy. On the average server I expect see a series of mountains as the PLE climbs then drops due to a data load or something along those lines. That's not the case here: Those spikes back in January suggest that the servers weren't really being used much. The PLE on the rg-sql01 seems to be somewhat consistent growing to 3 hours or so then dropping, but the rg-sql02 PLE looks like it might be all over the map. Instead of continuing to look at this high level gathering data view, I'm going to drill down on rg-sql02 and see what it's done for the last week: And now we begin to see where we might have an issue. Memory on this system is getting flushed every 1/2 hour or so. I'm going to check another metric, scans: Whoa! I'm going back to the system real quick to look at some disk information again for rg-sql02. Here is the average disk queue length on the server: and the transfers Right, I think I have a guess as to what's up here. We're seeing memory get flushed constantly and we're seeing lots of scans. The disks are queuing, especially that F drive, and there are lots of requests that correspond to the scans and the memory flushes. In short, we've got queries that are scanning the data, a lot, so we either have bad queries or bad indexes. I'm going back to the server overview for rg-sql02 and check the Top 10 expensive queries. I'm modifying it to show me the last 3 days and the totals, so I'm not looking at some maintenance routine that ran 10 minutes ago and is skewing the results: OK. I need to look into these queries that are getting executed this much. They're generating a lot of reads, but which queries are generating the most reads: Ow, all still going against the same database. This is where I'm going to temporarily leave SQL Monitor. What I want to do is connect up to the server, validate that the Warehouse database is using the F:\ drive (which I'll put money down it is) and then start seeing what's up with these queries. Part 1 of the Series Part 2 of the Series

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  • Book review (Book 6) - Wikinomics

    - by BuckWoody
    This is a continuation of the books I challenged myself to read to help my career - one a month, for year. You can read my first book review here. The book I chose for November 2011 was: Wikinomics: How Mass Collaboration Changes Everything, by Don Tapscott   Why I chose this Book: I’ve heard a lot about this book - was one of the “must read” kind of business books (many of which are very “fluffy”) and supposedly deals with collaborating using technology - so I want to see what it says about collaborative efforts and how I can leverage them. What I learned: I really disliked this book. I’ve never been a fan of the latest “business book”, and sadly that’s what this felt like to me. A “business book” is what I call a work that has a fairly simple concept to get across, and then proceeds to use various made-up terms, analogies and other mechanisms to fill hundreds of pages doing it. This perception is at my own – the book is pretty old, and these things go stale quickly. The author’s general point (at least what I took away from it) was: Open Source is good, proprietary is bad. Collaboration is the hallmark of successful companies. In my mind, you can save yourself the trouble of reading this work if you get these two concepts down. Don’t get me wrong – open source is awesome, and collaboration is a good thing, especially in places where it fits. But it’s not a panacea as the author seems to indicate. For instance, he continuously uses the example of MySpace to show a “2.0” company, which I think means that you can enter text as well as read it on a web page. All well and good. But we all know what happened to MySpace, and of course he missed the point entirely about this new web environment: low barriers to entry often mean low barriers to exit. And the open, collaborative company being the best model – well, I think we all know a certain computer company famous for phones and music that is arguably quite successful, and is probably one of the most closed, non-collaborative (at least with its customers) on the planet. So that sort of takes away that argument. The reality of business is far more complicated. Collaboration is an amazing tool, and should be leveraged heavily. However, at the end of the day, after you do your research you need to pick a strategy and stick with it. Asking thousands of people to assist you in building your product probably will not work well. Open Source is great – but some proprietary products are quite functional as well, have a long track record, are well supported, and will probably be upgraded. Everything has its place, so use what works where it is needed. There is no single answer, sadly. So did I waste my time reading the book? Did I make a bad choice? Not at all! Reading the opinions and thoughts of others is almost always useful, and it’s important to consider opinions other than your own. If nothing else, thinking through the process either convinces you that you are wrong, or helps you understand better why you are right.

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  • Speaker at the German Visual FoxPro Developer Conference 2003

    The following is an excerpt from the UniversalThread conference coverage of the German Visual FoxPro Developer Conference 2003 written by Hans-Otto Lochmann and Armin Neudert. Track: Visual FoxPro and Linux This track consists of 4 sessions presented on one day in one sequence. Originally the Linux portion of this track was to be presented by Whil Hentzen, the well-known publisher, book author and confer-ence speaker. Unfortunately some illness prevented him from joining this DevCon. Rainer got the bad news only on early Friday morning. It was definitely to late to find a replacement among the already invited speaker on such a short notice. So Rainer decided to take over these "three sessions in a row" by himself with "a little help from his friends". He hired a coach for him for the weekend and prepared slides and sessions by himself - the originally planed slides and session material were still in USA. Rainer survived barely an endless disaster of C0000005's due to various wrong configuration settings... At the presentation Jochen Kirstätter helped massively with technical details regarding Linux whereas Rainer did the slides and the presentation. Gerold Lübben then presented the MySQL part - as originally planned. This track concentrated on the how to run Visual FoxPro applications on Linux machines with the help of a Windows emulator like Wine. As more and more people use Linux machines in production (and not just for running servers), more and more invitations to bid for a development job includes the requirement to run the application in a Linux environment. If you would like to participate in such submissions, then you should get familiar with the open source operating system Linux and the open source Data Base system MySQL. [...] These sessions provided a broad, complete overview of where Linux fits into the current computing landscape from the perspective of a VFP developer, where VFP can be used with Linux, and a conceptual plan for how to approach the incorporation of Linux into your day-to-day work. In order for you to be able to work with a Linux back end, you're going to need to know something about how Linux works. The best way involves a two-step process: First, plunk down a Linux workstation on your desk next to your Windows machine and develop some experience with the new OS.Second, once you have a basic level of comfort with Linux, gained through your experience on a workstation, leverage that knowledge and learn to connect to a Linux server from your Windows machine. This track showed both of these processes: What you can expect when you set up your Linux work-station, how to set it up, how to connect to your Windows network, how to fit VFP into the mix, and even how you could use it to replace your Windows workstation in some cases. Also this track demonstrated how to connect to an existing Linux server, running MySQL or an another back end, and how to get your VFP apps talking to that back end data. This track also showed both of the positions you can take. Rainer disliked it wholeheartedly (the bad guy position in these talks) and Jochen loved it (the good guy and "typical Linux techie"-position we all love). These opposite position lasted for three sessions and both sides where shown with their Pros and Cons in live and lively discussions of the speakers (club banging was forbidden). Gerold Luebben showed how Visual Foxpro and MySQL can work together. MySQL is as one the most well known open SOURCE databases for nearly all platforms available. Particularly in eBusiness MySQL is well positioned and well known for its performance and its stability. Still we like Visual FoxPro more - for sure . [...]

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  • How to convert my backup.cmd into something I can run in Linux?

    - by blade19899
    Back in the day when i was using windows(and a noob at everything IT) i liked batch scripting so much that i wrote a lot of them and one i am pretty proud of that is my backup.cmd(see below). I am pretty basic with the linux bash sudo/apt-get/sl/ls/locate/updatedb/etc... I don't really know the full power of the terminal. If you see the code below can i get it to work under (Ubuntu)linux :) by rewriting some of the windows code with the linux equivalent (btw:this works under xp/vista/7 | dutch/english) @echo off title back it up :home cls echo ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» echo º º echo º typ A/B for the options º echo º º echo ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ͹ echo º º echo º "A"=backup options º echo º º echo º "B"=HARDDISK Options º echo º º echo º º echo ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍŒ set /p selection=Choose: Goto %selection% :A cls echo ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» echo º º echo º typ 1 to start that backup º echo º º echo ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ͹ echo º º echo º "A"=backup options º echo º È1=Documents,Pictures,Music,Videos,Downloads º echo º º echo º "B"=HARDDISK Options º echo º º echo ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍŒ set /p selection=Choose: Goto %selection% :B cls echo ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» echo º º echo º typ HD to start the disk check º echo º º echo ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ͹ echo º º echo º "A"=backup options º echo º º echo º "B"=HARDDISK Options º echo º ÈHD=find and repair bad sectors º echo º º echo ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍŒ set /p selection=Choose: Goto %selection% :1 cls if exist "%userprofile%\desktop" (set desk=desktop) else (set desk=Bureaublad) if exist "%userprofile%\documents" (set docs=documents) else (set docs=mijn documenten) if exist "%userprofile%\pictures" (set pics=pictures) else (echo cant find %userprofile%\pictures) if exist "%userprofile%\music" (set mus=music) else (echo cant find %userprofile%\music) if exist "%userprofile%\Videos" (set vids=videos) else (echo cant find %userprofile%\videos) if exist "%userprofile%\Downloads" (set down=downloads) else (echo cant find %userprofile%\Downloads) cls echo. examples (D:\) (D:\Backup) (D:\Backup\18-4-2011) echo. echo. if there is no "D:\backup" folder then the folder will be created echo. set drive= set /p drive=storage: echo start>>backup.log echo Name:%username%>>backup.log echo Date:%date%>>backup.log echo Time:%time%>>backup.log echo ========================================%docs%===========================================>>backup.log echo %docs% echo Source:"%userprofile%\%docs%" echo Destination:"%drive%\%username%\%docs%" echo %time%>>backup.log xcopy "%userprofile%\%docs%" "%drive%\%username%\%docs%" /E /I>>Backup.log echo 20%% cls echo ========================================"%pics%"=========================================>>backup.log echo "%pics%" echo Source:"%userprofile%\%pics%" echo Destination:"%drive%\%username%\%pics%" echo %time%>>backup.log xcopy "%userprofile%\%pics%" "%drive%\%username%\%pics%" /E /I>>Backup.log echo 40%% cls echo ========================================"%mus%"=========================================>>backup.log echo "%mus%" echo Source:"%userprofile%\%mus%" echo Destination:"%drive%\%username%\%mus%" echo %time%>>backup.log xcopy "%userprofile%\%mus%" "%drive%\%username%\%mus%" /E /I>>Backup.log echo 60%% cls echo ========================================"%vids%"========================================>>backup.log echo %vids% echo Source:"%userprofile%\%vids%" echo Destination:"%drive%\%username%\%vids%" echo %time%>>backup.log xcopy "%userprofile%\%vids%" "%drive%\%username%\%vids%" /E /I>>Backup.log echo 80%% cls echo ========================================"%down%"========================================>>backup.log echo "%down%" echo Source:"%userprofile%\%down%" echo Destination:"%drive%\%username%\%down%" echo %time%>>backup.log xcopy "%userprofile%\%down%" "%drive%\%username%\%down%" /E /I>>Backup.log echo end>>backup.log echo %username% %date% %time%>>backup.log echo 100%% cls echo backup Compleet copy "backup.log" "%drive%\%username%" del "backup.log" pushd "%drive%\%username%" echo close backup.log to continue with backup script "backup.log" echo press any key to retun to the main menu pause>nul goto :home :HD echo finds and repairs bad sectors echo typ in harddisk letter (C: D: E:) set HD= set /p HD=Hard Disk: chkdsk %HD% /F /R /X pause goto :home

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  • installArchives() failed: perl: warning: Setting locale failed.

    - by Alwin Doss
    I get the following error while updating ubuntu 12.04 LTS installArchives() failed: perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... (Reading database ... (Reading database ... 5%% (Reading database ... 10%% (Reading database ... 15%% (Reading database ... 20%% (Reading database ... 25%% (Reading database ... 30%% (Reading database ... 35%% (Reading database ... 40%% (Reading database ... 45%% (Reading database ... 50%% (Reading database ... 55%% (Reading database ... 60%% (Reading database ... 65%% (Reading database ... 70%% (Reading database ... 75%% (Reading database ... 80%% (Reading database ... 85%% (Reading database ... 90%% (Reading database ... 95%% (Reading database ... 100%% (Reading database ... 430284 files and directories currently installed.) Preparing to replace libxml2-dev 2.7.8.dfsg-5.1ubuntu4.1 (using .../libxml2-dev_2.7.8.dfsg-5.1ubuntu4.2_i386.deb) ... Unpacking replacement libxml2-dev ... Preparing to replace libxml2 2.7.8.dfsg-5.1ubuntu4.1 (using .../libxml2_2.7.8.dfsg-5.1ubuntu4.2_i386.deb) ... Unpacking replacement libxml2 ... Preparing to replace gstreamer0.10-plugins-bad 0.10.22.3-2ubuntu2 (using .../gstreamer0.10-plugins-bad_0.10.22.3-2ubuntu2.1_i386.deb) ... Unpacking replacement gstreamer0.10-plugins-bad ... Preparing to replace libgstreamer-plugins-bad0.10-0 0.10.22.3-2ubuntu2 (using .../libgstreamer-plugins-bad0.10-0_0.10.22.3-2ubuntu2.1_i386.deb) ... Unpacking replacement libgstreamer-plugins-bad0.10-0 ... Preparing to replace ubuntu-keyring 2011.11.21 (using .../ubuntu-keyring_2011.11.21.1_all.deb) ... /var/lib/dpkg/info/samba4.postinst: 14: /var/lib/dpkg/info/samba4.postinst: /usr/share/samba/setoption.pl: Permission denied dpkg: error processing samba4 (--configure): subprocess installed post-installation script returned error exit status 126

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  • Inside Red Gate - Experimenting In Public

    - by Simon Cooper
    Over the next few weeks, we'll be performing experiments on SmartAssembly to confirm or refute various hypotheses we have about how people use the product, what is stopping them from using it to its full extent, and what we can change to make it more useful and easier to use. Some of these experiments can be done within the team, some within Red Gate, and some need to be done on external users. External testing Some external testing can be done by standard usability tests and surveys, however, there are some hypotheses that can only be tested by building a version of SmartAssembly with some things in the UI or implementation changed. We'll then be able to look at how the experimental build is used compared to the 'mainline' build, which forms our baseline or control group, and use this data to confirm or refute the relevant hypotheses. However, there are several issues we need to consider before running experiments using separate builds: Ideally, the user wouldn't know they're running an experimental SmartAssembly. We don't want users to use the experimental build like it's an experimental build, we want them to use it like it's the real mainline build. Only then will we get valid, useful, and informative data concerning our hypotheses. There's no point running the experiments if we can't find out what happens after the download. To confirm or refute some of our hypotheses, we need to find out how the tool is used once it is installed. Fortunately, we've applied feature usage reporting to the SmartAssembly codebase itself to provide us with that information. Of course, this then makes the experimental data conditional on the user agreeing to send that data back to us in the first place. Unfortunately, even though this does limit the amount of useful data we'll be getting back, and possibly skew the data, there's not much we can do about this; we don't collect feature usage data without the user's consent. Looks like we'll simply have to live with this. What if the user tries to buy the experiment? This is something that isn't really covered by the Lean Startup book; how do you support users who give you money for an experiment? If the experiment is a new feature, and the user buys a license for SmartAssembly based on that feature, then what do we do if we later decide to pivot & scrap that feature? We've either got to spend time and money bringing that feature up to production quality and into the mainline anyway, or we've got disgruntled customers. Either way is bad. Again, there's not really any good solution to this. Similarly, what if we've removed some features for an experiment and a potential new user downloads the experimental build? (As I said above, there's no indication the build is an experimental build, as we want to see what users really do with it). The crucial feature they need is missing, causing a bad trial experience, a lost potential customer, and a lost chance to help the customer with their problem. Again, this is something not really covered by the Lean Startup book, and something that doesn't have a good solution. So, some tricky issues there, not all of them with nice easy answers. Turns out the practicalities of running Lean Startup experiments are more complicated than they first seem!

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  • What Counts For a DBA – Decisions

    - by Louis Davidson
    It’s Friday afternoon, and the lead DBA, a very talented guy, is getting ready to head out for two well-earned weeks of vacation, with his family, when this error message pops up in his inbox: Msg 211, Level 23, State 51, Line 1. Possible schema corruption. Run DBCC CHECKCATALOG. His heart sinks. It’s ten…no eight…minutes till it’s time to walk out the door. He glances around at his coworkers, competent to handle many problems, but probably not up to the challenge of fixing possible database corruption. What does he do? After a few agonizing moments of indecision, he clicks shut his laptop. He’ll just wait and see. It was unlikely to come to anything; after all, it did say “possible” schema corruption, not definite. In that moment, his fate was sealed. The start of the solution to the problem (run DBCC CHECKCATALOG) had been right there in the error message. Had he done this, or at least took two of those eight minutes to delegate the task to a coworker, then he wouldn’t have ended up spending two-thirds of an idyllic vacation (for the rest of the family, at least) dealing with a problem that got consistently worse as the weekend progressed until the entire system was down. When I told this story to a friend of mine, an opera fan, he smiled and said it described the basic plotline of almost every opera or ‘Greek Tragedy’ ever written. The particular joy in opera, he told me, isn’t the warbly voiced leading ladies, or the plump middle-aged romantic leads, or even the music. No, what packs the opera houses in Italy is the drama of characters who, by the very nature of their life-experiences and emotional baggage, make all sorts of bad choices when faced with ordinary decisions, and so move inexorably to their fate. The audience is gripped by the spectacle of exotic characters doomed by their inability to see the obvious. I confess, my personal experience with opera is limited to Bugs Bunny in “What’s Opera, Doc?” (Elmer Fudd is a great example of a bad decision maker, if ever one existed), but I was struck by my friend’s analogy. If all the DBA cubicles were a stage, I think we would hear many similarly tragic tales, played out to music: “Error handling? We write our code to never experience errors, so nah…“ “Backups failed today, but it’s okay, we’ll back up tomorrow (we’ll back up tomorrow)“ And similarly, they would leave their audience gasping, not necessarily at the beauty of the music, or poetry of the lyrics, but at the inevitable, grisly fate of the protagonists. If you choose not to use proper error handling, or if you choose to skip a backup because, hey, you haven’t had a server crash in 10 years, then inevitably, in that moment you expected to be enjoying a vacation, or a football game, with your family and friends, you will instead be sitting in front of a computer screen, paying for your poor choices. Tragedies are very much part of IT. Most of a DBA’s day to day work has limited potential to wreak havoc; paperwork, timesheets, random anonymous threats to developers, routine maintenance and whatnot. However, just occasionally, you, as a DBA, will face one of those decisions that really matter, and which has the possibility to greatly affect your future and the future of your user’s data. Make those decisions count, and you’ll avoid the tragic fate of many an operatic hero or villain.

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  • Azure Mobile Services: lessons learned

    - by svdoever
    When I first started using Azure Mobile Services I thought of it as a nice way to: authenticate my users - login using Twitter, Google, Facebook, Windows Live create tables, and use the client code to create the columns in the table because that is not possible in the Azure Mobile Services UI run some Javascript code on the table crud actions (Insert, Update, Delete, Read) schedule a Javascript to run any 15 or more minutes I had no idea of the magic that was happening inside… where is the data stored? Is it a kind of big table, are relationships between tables possible? those Javascripts on the table crud actions, is that interpreted, what is that exactly? After working for some time with Azure Mobile Services I became a lot wiser: Those tables are just normal tables in an Azure SQL Server 2012 Creating the table columns through client code sucks, at least from my Javascript code, because the columns are deducted from the sent JSON data, and a datetime field is sent as string in JSON, so a string type column is created instead of a datetime column You can connect with SQL Management Studio to the Azure SQL Server, and although you can’t manage your columns through the SQL Management Studio UI, it is possible to just run SQL scripts to drop and create tables and indices When you create a table through SQL script, add the table with the same name in the Azure Mobile Services UI to hook it up and be able to access the table through the provided abstraction layer You can also go to the SQL Database through the Azure Mobile Services UI, and from there get in a web based SQL management studio where you can create columns and manage your data The table crud scripts and the scheduler scripts are full blown node.js scripts, introducing a lot of power with great performance The web based script editor is really powerful, I do most of my editing currently in the editor which has syntax highlighting and code completing. While editing the code JsHint is used for script validation. The documentation on Azure Mobile Services is… suboptimal. It is such a pity that there is no way to comment on it so the community could fill in the missing holes, like which node modules are already loaded, and which modules are available on Azure Mobile Services. Soon I was hacking away on Azure Mobile Services, creating my own database tables through script, and abusing the read script of an empty table named query to implement my own set of “services”. The latest updates to Azure Mobile Services described in the following posts added some great new features like creating web API’s, use shared code from your scripts, command line tools for managing Azure Mobile Services (upload and download scripts for example), support for node modules and git support: http://weblogs.asp.net/scottgu/archive/2013/06/14/windows-azure-major-updates-for-mobile-backend-development.aspx http://blogs.msdn.com/b/carlosfigueira/archive/2013/06/14/custom-apis-in-azure-mobile-services.aspx http://blogs.msdn.com/b/carlosfigueira/archive/2013/06/19/custom-api-in-azure-mobile-services-client-sdks.aspx In the mean time I rewrote all my “service-like” table scripts to API scripts, which works like a breeze. Bad thing with the current state of Azure Mobile Services is that the git support is not working if you are a co-administrator of your Azure subscription, and not and administrator (as in my case). Another bad thing is that Cross Origin Request Sharing (CORS) is not supported for the API yet, so no go yet from the browser client for API’s, which is my case. See http://social.msdn.microsoft.com/Forums/windowsazure/en-US/2b79c5ea-d187-4c2b-823a-3f3e0559829d/known-limitations-for-source-control-and-custom-api-features for more on these and other limitations. In his talk at Build 2013 Josh Twist showed that there is a work-around for accessing shared script code from the table scripts as well (another limitation mentioned in the post above). I could not find that code in the Votabl2 code example from the presentation at https://github.com/joshtwist/votabl2, but we can grab it from the presentation when it comes online on Channel9. By the way: you can always express your needs and ideas at http://mobileservices.uservoice.com, that’s the place they are listening to (I hope!).

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  • How the number of indexes built on a table can impact performances?

    - by Davide Mauri
    We all know that putting too many indexes (I’m talking of non-clustered index only, of course) on table may produce performance problems due to the overhead that each index bring to all insert/update/delete operations on that table. But how much? I mean, we all agree – I think – that, generally speaking, having many indexes on a table is “bad”. But how bad it can be? How much the performance will degrade? And on a concurrent system how much this situation can also hurts SELECT performances? If SQL Server take more time to update a row on a table due to the amount of indexes it also has to update, this also means that locks will be held for more time, slowing down the perceived performance of all queries involved. I was quite curious to measure this, also because when teaching it’s by far more impressive and effective to show to attended a chart with the measured impact, so that they can really “feel” what it means! To do the tests, I’ve create a script that creates a table (that has a clustered index on the primary key which is an identity column) , loads 1000 rows into the table (inserting 1000 row using only one insert, instead of issuing 1000 insert of one row, in order to minimize the overhead needed to handle the transaction, that would have otherwise ), and measures the time taken to do it. The process is then repeated 16 times, each time adding a new index on the table, using columns from table in a round-robin fashion. Test are done against different row sizes, so that it’s possible to check if performance changes depending on row size. The result are interesting, although expected. This is the chart showing how much time it takes to insert 1000 on a table that has from 0 to 16 non-clustered indexes. Each test has been run 20 times in order to have an average value. The value has been cleaned from outliers value due to unpredictable performance fluctuations due to machine activity. The test shows that in a  table with a row size of 80 bytes, 1000 rows can be inserted in 9,05 msec if no indexes are present on the table, and the value grows up to 88 (!!!) msec when you have 16 indexes on it This means a impact on performance of 975%. That’s *huge*! Now, what happens if we have a bigger row size? Say that we have a table with a row size of 1520 byte. Here’s the data, from 0 to 16 indexes on that table: In this case we need near 22 msec to insert 1000 in a table with no indexes, but we need more that 500msec if the table has 16 active indexes! Now we’re talking of a 2410% impact on performance! Now we can have a tangible idea of what’s the impact of having (too?) many indexes on a table and also how the size of a row also impact performances. That’s why the golden rule of OLTP databases “few indexes, but good” is so true! (And in fact last week I saw a database with tables with 1700bytes row size and 23 (!!!) indexes on them!) This also means that a too heavy denormalization is really not a good idea (we’re always talking about OLTP systems, keep it in mind), since the performance get worse with the increase of the row size. So, be careful out there, and keep in mind the “equilibrium” is the key world of a database professional: equilibrium between read and write performance, between normalization and denormalization, between to few and too may indexes. PS Tests are done on a VMWare Workstation 7 VM with 2 CPU and 4 GB of Memory. Host machine is a Dell Precsioni M6500 with i7 Extreme X920 Quad-Core HT 2.0Ghz and 16Gb of RAM. Database is stored on a SSD Intel X-25E Drive, Simple Recovery Model, running on SQL Server 2008 R2. If you also want to to tests on your own, you can download the test script here: Open TestIndexPerformance.sql

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  • Logging errors caused by exceptions deep in the application

    - by Kaleb Pederson
    What are best-practices for logging deep within an application's source? Is it bad practice to have multiple event log entries for a single error? For example, let's say that I have an ETL system whose transform step involves: a transformer, pipeline, processing algorithm, and processing engine. In brief, the transformer takes in an input file, parses out records, and sends the records through the pipeline. The pipeline aggregates the results of the processing algorithm (which could do serial or parallel processing). The processing algorithm sends each record through one or more processing engines. So, I have at least four levels: Transformer - Pipeline - Algorithm - Engine. My code might then look something like the following: class Transformer { void Process(InputSource input) { try { var inRecords = _parser.Parse(input.Stream); var outRecords = _pipeline.Transform(inRecords); } catch (Exception ex) { var inner = new ProcessException(input, ex); _logger.Error("Unable to parse source " + input.Name, inner); throw inner; } } } class Pipeline { IEnumerable<Result> Transform(IEnumerable<Record> records) { // NOTE: no try/catch as I have no useful information to provide // at this point in the process var results = _algorithm.Process(records); // examine and do useful things with results return results; } } class Algorithm { IEnumerable<Result> Process(IEnumerable<Record> records) { var results = new List<Result>(); foreach (var engine in Engines) { foreach (var record in records) { try { engine.Process(record); } catch (Exception ex) { var inner = new EngineProcessingException(engine, record, ex); _logger.Error("Engine {0} unable to parse record {1}", engine, record); throw inner; } } } } } class Engine { Result Process(Record record) { for (int i=0; i<record.SubRecords.Count; ++i) { try { Validate(record.subRecords[i]); } catch (Exception ex) { var inner = new RecordValidationException(record, i, ex); _logger.Error( "Validation of subrecord {0} failed for record {1}", i, record ); } } } } There's a few important things to notice: A single error at the deepest level causes three log entries (ugly? DOS?) Thrown exceptions contain all important and useful information Logging only happens when failure to do so would cause loss of useful information at a lower level. Thoughts and concerns: I don't like having so many log entries for each error I don't want to lose important, useful data; the exceptions contain all the important but the stacktrace is typically the only thing displayed besides the message. I can log at different levels (e.g., warning, informational) The higher level classes should be completely unaware of the structure of the lower-level exceptions (which may change as the different implementations are replaced). The information available at higher levels should not be passed to the lower levels. So, to restate the main questions: What are best-practices for logging deep within an application's source? Is it bad practice to have multiple event log entries for a single error?

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  • Error while updating

    - by Alwin Doss
    I get the following error while updating ubuntu 12.04 LTS installArchives() failed: perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... (Reading database ... (Reading database ... 5%% (Reading database ... 10%% (Reading database ... 15%% (Reading database ... 20%% (Reading database ... 25%% (Reading database ... 30%% (Reading database ... 35%% (Reading database ... 40%% (Reading database ... 45%% (Reading database ... 50%% (Reading database ... 55%% (Reading database ... 60%% (Reading database ... 65%% (Reading database ... 70%% (Reading database ... 75%% (Reading database ... 80%% (Reading database ... 85%% (Reading database ... 90%% (Reading database ... 95%% (Reading database ... 100%% (Reading database ... 430284 files and directories currently installed.) Preparing to replace libxml2-dev 2.7.8.dfsg-5.1ubuntu4.1 (using .../libxml2-dev_2.7.8.dfsg-5.1ubuntu4.2_i386.deb) ... Unpacking replacement libxml2-dev ... Preparing to replace libxml2 2.7.8.dfsg-5.1ubuntu4.1 (using .../libxml2_2.7.8.dfsg-5.1ubuntu4.2_i386.deb) ... Unpacking replacement libxml2 ... Preparing to replace gstreamer0.10-plugins-bad 0.10.22.3-2ubuntu2 (using .../gstreamer0.10-plugins-bad_0.10.22.3-2ubuntu2.1_i386.deb) ... Unpacking replacement gstreamer0.10-plugins-bad ... Preparing to replace libgstreamer-plugins-bad0.10-0 0.10.22.3-2ubuntu2 (using .../libgstreamer-plugins-bad0.10-0_0.10.22.3-2ubuntu2.1_i386.deb) ... Unpacking replacement libgstreamer-plugins-bad0.10-0 ... Preparing to replace ubuntu-keyring 2011.11.21 (using .../ubuntu-keyring_2011.11.21.1_all.deb) ... /var/lib/dpkg/info/samba4.postinst: 14: /var/lib/dpkg/info/samba4.postinst: /usr/share/samba/setoption.pl: Permission denied dpkg: error processing samba4 (--configure): subprocess installed post-installation script returned error exit status 126

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  • Inside Red Gate - Exercising Externally

    - by simonc
    Over the next few weeks, we'll be performing experiments on SmartAssembly to confirm or refute various hypotheses we have about how people use the product, what is stopping them from using it to its full extent, and what we can change to make it more useful and easier to use. Some of these experiments can be done within the team, some within Red Gate, and some need to be done on external users. External testing Some external testing can be done by standard usability tests and surveys, however, there are some hypotheses that can only be tested by building a version of SmartAssembly with some things in the UI or implementation changed. We'll then be able to look at how the experimental build is used compared to the 'mainline' build, which forms our baseline or control group, and use this data to confirm or refute the relevant hypotheses. However, there are several issues we need to consider before running experiments using separate builds: Ideally, the user wouldn't know they're running an experimental SmartAssembly. We don't want users to use the experimental build like it's an experimental build, we want them to use it like it's the real mainline build. Only then will we get valid, useful, and informative data concerning our hypotheses. There's no point running the experiments if we can't find out what happens after the download. To confirm or refute some of our hypotheses, we need to find out how the tool is used once it is installed. Fortunately, we've applied feature usage reporting to the SmartAssembly codebase itself to provide us with that information. Of course, this then makes the experimental data conditional on the user agreeing to send that data back to us in the first place. Unfortunately, even though this does limit the amount of useful data we'll be getting back, and possibly skew the data, there's not much we can do about this; we don't collect feature usage data without the user's consent. Looks like we'll simply have to live with this. What if the user tries to buy the experiment? This is something that isn't really covered by the Lean Startup book; how do you support users who give you money for an experiment? If the experiment is a new feature, and the user buys a license for SmartAssembly based on that feature, then what do we do if we later decide to pivot & scrap that feature? We've either got to spend time and money bringing that feature up to production quality and into the mainline anyway, or we've got disgruntled customers. Either way is bad. Again, there's not really any good solution to this. Similarly, what if we've removed some features for an experiment and a potential new user downloads the experimental build? (As I said above, there's no indication the build is an experimental build, as we want to see what users really do with it). The crucial feature they need is missing, causing a bad trial experience, a lost potential customer, and a lost chance to help the customer with their problem. Again, this is something not really covered by the Lean Startup book, and something that doesn't have a good solution. So, some tricky issues there, not all of them with nice easy answers. Turns out the practicalities of running Lean Startup experiments are more complicated than they first seem! Cross posted from Simple Talk.

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  • MVC Communication Pattern

    - by Kedu
    This is kind of a follow up question to this http://stackoverflow.com/questions/23743285/model-view-controller-and-callbacks, but I wanted to post it separately, because its kind of a different topic. I'm working on a multiplayer cardgame for the Android platform. I split the project into MVC which fits the needs pretty good, but I'm currently stuck because I can't figure out a good way to communicate between the different parts. I have everything setup and working with the controller being a big state machine, which is called over and over from the gameloop, and calls getter methods from the GUI and the android/network part to get the input. The input itself in the GUI and network is set by inputlisteners that set a local variable which I read in the getter method. So far so good, this is working. But my problem is, the controller has to check every input separately,so if I want to add an input I have to check in which states its valid and call the getter method from all these states. This is not good, and lets the code look pretty ugly, makes additions uncomfortable and adds redundance. So what I've got from the question I mentioned above is that some kind of command or event pattern will fit my needs. What I want to do is to create a shared and threadsafe queue in the controller and instead of calling all these getter methods, I just check the queue for new input and proceed it. On the other side, the GUI and network don't have all these getters, but instead create an event or command and send it to the controller through, for example, observer/observable. Now my problem: I can't figure out a way, for these commands/events to fit a common interface (which the queue can store) and still transport different kind of data (button clicks, cards that are played, the player id the command comes from, synchronization data etc.). If I design the communication as command pattern, I have to stick all the information that is needed to execute the command into it when its created, that's impossible because the GUI or network has no knowledge of all the things the controller needs to execute stuff that needs to be done when for example a card is played. I thought about getting this stuff into the command when executing it. But over all the different commands I have, I would need all the information the controller has, and thus give the command a reference to the controller which would make everything in it public, which is real bad design I guess. So, I could try some kind of event pattern. I have to transport data in the event. So, like the command, I would have an interface, which all events have in common, and can be stored in the shared queue. I could create a big enum with all the different events that a are possible, save one of these enums in the actual event, and build a big switch case for the events, to proceed different stuff for different events. The problem here: I have different data for all the events. But I need a common interface, to store the events in a queue. How do I get the specific data, if I can only access the event through the interface? Even if that wouldn't be a problem, I'm creating another big switch case, which looks ugly, and when i want to add a new event, I have to create the event itself, the case, the enum, and the method that's called with the data. I could of course check the event with the enum and cast it to its type, so I can call event type specific methods that give me the data I need, but that looks like bad design too.

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