Search Results

Search found 4126 results on 166 pages for 'bitwise operations'.

Page 132/166 | < Previous Page | 128 129 130 131 132 133 134 135 136 137 138 139  | Next Page >

• How should a process running outside Internet Explorer talk to JavaScript running inside it?

  - by Paul Crowley

  This may well be impossible; either way I'm sure people here will know. I'm trying to reduce three "OK" prompts to two. As part of my application, users will download and run an executable I supply; call it privileged.exe. privileged.exe will have a coda that asks for the highest privileges available. That's two OK prompts, one to run privileged.exe and one for UAC. I'd like privileged.exe to then install an ActiveX control, browser plugin or some such. The purpose of this ActiveX control is to allow the JavaScript running inside the browser to talk to the running privileged.exe process, to allow the user to perform certain operations that require high privileges by making choices in the browser. And I'd ideally like this to happen without the user having to restart their browser or explicitly OK the installation of the ActiveX control. Is that possible? Can you install an ActiveX control from outside the browser in such a way that it becomes immediately available to pages running inside the browser? Or should I give up, and allow the user to be explicitly prompted to install the ActiveX control?

  Read the article

• Fast, easy, and secure method to perform DB actions with GET

  - by rob - not a robber

  Hey All, Sort of a methods/best practices question here that I am sure has been addressed, yet I can't find a solution based on the vague search terms I enter. I know starting off the question with "Fast and easy" will probably draw out a few sighs, so my apologies. Here is the deal. I have a logged in area where an ADMIN can do a whole host of POST operations to input data relating to their profile. The way I have data structured is pretty distinct and well segmented in most tables as it relates to the ID of the admin. Now, I have a table where I dump one type of data into and differentiate this data by assigning the ADMIN's unique ID to each record. In other words, all ADMINs have this one type of data writing to this table. I just differentiate by the ADMIN ID with each record. I was planning on letting the ADMIN remove these records by clicking on a link with a query string - obviously using GET. Obviously, the query structure is in the link so any logged in admin could then exploit the URL and delete a competitor's records. Is the only way to safely do this through POST or should I pass through the session info that includes password and validate it against the ADMIN ID that is requesting the delete? This is obviously much more work for me. As they said in the auto repair biz I used to work in... there are 3 ways to do a job: Fast, Good, and Cheap. You can only have two at a time. Fast and cheap will not be good. Good and cheap will not have fast turnaround. Fast and good will NOT be cheap. haha I guess that applies here... can never have Fast, Easy and Secure all at once ;) Thanks in advance...

  Read the article

• Syncing magento database froms development to production

  - by ringerce

  I use git for version control. I have a development, staging and production environment. When I finish in development I push to staging for review by the client. When approved, I push changes from staging to production. That works fine as long as there is no database changes. What happens if I install modules via Magento connect on local development and it makes database modifications. How would I push those changes up to the production server since the production server is always changing? Edit: I wrote two shell scripts. One that pulls the production database down to my development server, replaces base url with develpment url and updates my development db accordingly. It also leaves the production sql dump behind to be added to my git repo. I'm not really sure if it's beneficial to keep the raw dumps in source control but I'm going to try it out. The second scripts moves the development database up to staging and essentially performs the same operations as the first. Now when it comes time to move to production I pull the updated production repo into the production server and allow magento to do it's thing. I also started using SQLYog recently and it has a database comparison wizard which will give me the differences in my development and production databases and allow me to merge the changes in selectively. It always creates a migration script that I added to source control as well. If anything goes wrong I can run the comparison to see if anything was missed. Does this sounds like a decent workflow to you guys?

  Read the article

• What database systems should an startup company consider?

  - by Am

  Right now I'm developing the prototype of a web application that aggregates large number of text entries from a large number of users. This data must be frequently displayed back and often updated. At the moment I store the content inside a MySQL database and use NHibernate ORM layer to interact with the DB. I've got a table defined for users, roles, submissions, tags, notifications and etc. I like this solution because it works well and my code looks nice and sane, but I'm also worried about how MySQL will perform once the size of our database reaches a significant number. I feel that it may struggle performing join operations fast enough. This has made me think about non-relational database system such as MongoDB, CouchDB, Cassandra or Hadoop. Unfortunately I have no experience with either. I've read some good reviews on MongoDB and it looks interesting. I'm happy to spend the time and learn if one turns out to be the way to go. I'd much appreciate any one offering points or issues to consider when going with none relational dbms?

  Read the article

• Problems migrating databinding in VB.NET from Winforms to ASP.NET 2.0

  - by David

  And this was supposed to be so easy... I have existing business and data access layers that handle the retrieval and update of the data in question. These work great with the existing Winforms application (.Net V2.0) Now, in trying to write a new web-based UI, I'm running into all sorts of problems (last time I wrote asp.net code was in 1.1). Specifically, I can't data bind a text box to a business object. Oh, sure there's the ObjectDataSource but that wants to know how to do CRUD operations on the data. What I'm looking for is something that acts like the 'classic' binding objects so that, in my code, it's as simple as retrieving the object and doing a a refresh. The data component like FormView and DetailsView are so generic-looking that it's ridiculous. The existing application would have tabbed dialogs, text boxes grouped by panels, etc. On top of that, I have a directive to use master pages and unless one control causes it, I can't seem to get the content section to expand. I can't just put a text box 'below' the bottom of "Content1" and have it resize the content section - which gives me the same results as an earlier question I posted when the footer wasn't being 'pushed down' - relative position solved that but doesn't seem to solve it with placing small text boxes in the area. What I want is fairly simple. Something like: bindingobject.datasource = businessdataobject bindingobject.refresh ...and have the text boxes refresh with the new values. Likewise to have 'businessdataobject' properties updated as the user enters new data. I was able to do this with the GridView (grdRequests.DataSource = lstRequests) by making a list of asp:BoundField tags inside the collection of the GridView. Am I tilting at windmills here?

  Read the article

• Building a control-flow graph from an AST with a visitor pattern using Java

  - by omegatai

  Hi guys, I'm trying to figure out how to implement my LEParserCfgVisitor class as to build a control-flow graph from an Abstract-Syntax-Tree already generated with JavaCC. I know there are tools that already exist, but I'm trying to do it in preparation for my Compilers final. I know I need to have a data structure that keeps the graph in memory, and I want to be able to keep attributes like IN, OUT, GEN, KILL in each node as to be able to do a control-flow analysis later on. My main problem is that I haven't figured out how to connect the different blocks together, as to have the right edge between each blocks depending on their nature: branch, loops, etc. In other words, I haven't found an explicit algorithm that could help me build my visitor. Here is my empty Visitor. You can see it works on basic langage expressions, like if, while and basic operations (+,-,x,^,...) public class LEParserCfgVisitor implements LEParserVisitor { public Object visit(SimpleNode node, Object data) { return data; } public Object visit(ASTProgram node, Object data) { data = node.childrenAccept(this, data); return data; } public Object visit(ASTBlock node, Object data) { } public Object visit(ASTStmt node, Object data) { } public Object visit(ASTAssignStmt node, Object data) { } public Object visit(ASTIOStmt node, Object data) { } public Object visit(ASTIfStmt node, Object data) { } public Object visit(ASTWhileStmt node, Object data) { } public Object visit(ASTExpr node, Object data) { } public Object visit(ASTAddExpr node, Object data) { } public Object visit(ASTFactExpr node, Object data) { } public Object visit(ASTMultExpr node, Object data) { } public Object visit(ASTPowerExpr node, Object data) { } public Object visit(ASTUnaryExpr node, Object data) { } public Object visit(ASTBasicExpr node, Object data) { } public Object visit(ASTFctExpr node, Object data) { } public Object visit(ASTRealValue node, Object data) { } public Object visit(ASTIntValue node, Object data) { } public Object visit(ASTIdentifier node, Object data) { } } Can anyone give me a hand? Thanks!

  Read the article

• C++ iterators, default initialization and what to use as an uninitialized sentinel.

  - by Hassan Syed

  The Context I have a custom template container class put together from a map and vector. The map resolves a string to an ordinal, and the vector resolves an ordinal (only an initial string to ordinal lookup is done, future references are to the vector) to the entry. The entries are modified intrusively to contain a a bool "assigned" and an iterator_type which is a const_iterator to the container class's map. My container class will use RCF's serialization code (which models boost::serialization) to serialize my container classes to nodes in a network. Serializing iterator's is not possible, or a can of worms, and I can easily regenerate them onces the vectors and maps are serialized on the remote site. The Question I need to default initialize, and be able to test that the iterator has not been assigned to (if it is assigned it is valid, if not it is invalid). Since map iterators are not invalidated upon operations performed on it (unless of course items are removed :D) am I to assume that map<x,y>::end() is a valid sentinel (regardless of the state of the map -- i.e., it could be empty) to initialize to ? I will always have access to the parent map, I'm just unsure wheather end() is the same as the map contents change. I don't want to use another level of indirection (--i.e., boost::optional) to achieve my goal, I'd rather forego compiler checks to correct logic, but it would be nice if I didn't need to. Misc This question exists, but most of its content seems non-sense. Assigning a NULL to an iterator is invalid according to g++ and clang++. This is another similar question, but it focuses on the common use-cases of iterators, which generally tends to be using the iterator to iterate, ofcourse in this use-case the state of the container isn't meant to change whilst iteration is going on.

  Read the article

• Accessing a share point site using the object model.

  - by Prashanth

  Hi I am trying to access a share point site using the SP object model from a console application. I am trying to do something like this.. SPSite site = new SPSite(sitePath) //Operations go here This works fine when the share point site and the console app are on the same machine. However when the console app and the site are on different machines, I get an error "The Web application at "http://server/url" could not be found. Verify that you have typed the URL correctly. If the URL should be serving existing content, the system administrator may need to add a new request URL mapping to the intended application" Here are the things that I have already done: 1) I have tried accessing the site via both IP address as well as machine name, assuming that it could be a DNS resolution issue. 2) Initially I impersonated using a farm admin account, still i could not access. Then I added myself as the farm admin, still no joy. 4) The site is accessible via IE. So it is not a permission issue I guess. 5) I have tried almost all the solutions suggested by various links obtained by googling the error message. I am trying this on share point 2010. A similar issue occurs on 2007 also. Sometimes its kind of frustrating to do SharePoint development , since I get the feeling of stumbling from one error to the next, with no clue as to what could be wrong and the error messages not being helpful in the least :(

  Read the article

• how to return response from post in a variable? jQuery

  - by robertdd

  i use this function to return the response of post: $.sendpost = function(){ return jQuery.post('inc/operations.php', {'operation':'test'}, "json"); }, i want to make something like this: in: $.another = function(){ var sendpost = $.sendpost(); alert(sendpost); } but i get: [object XMLHttpRequest] if i print the object with: jQuery.each(sendpost, function(i, val) { $(".displaydetails").append(i + " => " + val + "<br/>"); }); i get: details abort => function () { x && h.call(x); g("abort"); } dispatchEvent => function dispatchEvent() { [native code] } removeEventListener => function removeEventListener() { [native code] } open => function open() { [native code] } setRequestHeader => function setRequestHeader() { [native code] } onreadystatechange => [xpconnect wrapped nsIDOMEventListener] send => function send() { [native code] } readyState => 4 status => 200 getResponseHeader => function getResponseHeader() { [native code] } responseText => mdaaa from php how to return only the response in the variable?

  Read the article

• iPhone: How to Determine Average Light/Dark of an Area of an UIImage

  - by TechZen

  I need to place labels with a transparent background over a variable-content UIImage. Readability will vary significantly depending on the relationship between the color of the label's text and the color/luminosity of the area of the image displayed under the label. Since the image will be constantly changing, the color of the label's text needs to change in sync. I have found several techniques for determining the color, perceived luminosity etc of a single pixel. However, I need to rather quickly (while a view loads) determine the rough perceived color/luminosity of an area of the UIImage under the frame of the UILabel. I presume I will also need to measure the alpha because the same color/luminosity looks different at different alpha values. Is there a way to calculate such a value for an area? Will I be reduced to simply summing pixels? If it comes to that, is there an algorithm to accomplish this? I've thought of two possible approaches: Perform some "folding" operations i.e. combining pixels from one half of the area to the other half. Then repeat until I get a single value. Would this be practical? How would you logically combine pixels to average their perceived color/luminosity? Sample a statistically significant number of pixels in the area and then combine them (somehow) to get a rough measure. I think this problem comes up a lot these days with people being so found of customizing backgrounds. Seems like something that would be worth my time to bang out a category or class to handle this and then share it around.

  Read the article

• Is it possible to definitively identify whether a DML command was issued from a stored procedure?

  - by Ed Harper

  I have inherited a SQL Server 2008 database to which calling applications have access through stored procedures. Each table in the database has a shadow audit table into which Insert/Update/Delete operations for are logged. Performance testing on populating the audit tables showed that inserting the audit records using OUTPUT clauses was 20% or so faster than using triggers, so this has been implemented in the stored procedures. However, because this design cannot track changes made directly to the tables through DML statements issued directly against the tables, triggers have also been implemented which use the value of @@NESTLEVEL to determine whether or not to run the trigger (the assumption being that all DML run through stored procedures will have @@NESTLEVEL 1). i.e. the body of the trigger code looks something like: IF @@NESTLEVEL = 1 -- implies call is direct sql so generate history from here BEGIN ... insert into audit table This design is flawed because it won't track updates where DML statements are executed in dynamic SQL, or any other context where @@NESTLEVEL is raised above 1. Can anyone suggest a completely reliable method we can use in the triggers to execute them only if not triggered by a stored procedure? Or is this (as I suspect) not possible?

  Read the article

• How to use a VB usercontrol on a C# page?

  - by ks78

  Hopefully someone will be able to point me in the right direction. I've created a usercontrol in VB that handles paging more efficiently than the DataPager (at least for very large datasets). I'd like to use it in a C# project, but I've been having trouble getting it to work. I've tried simply adding PagingControl.ascx to the C# project, but when I do that the markup and VB code behind don't seem to see each other. --Is this a namespace issue? I've tried adding the PagingControl.ascx to its own VB project, then adding that project to the C# project's solution, as well as a reference. --That almost works. I can register the PagingControl usercontrol in the markup. I can access the usercontrol's properties in the code behind, but any property that involves the UI of the usercontrol fails. Its seems as if the usercontrol's form hasn't had a chance to load by the time the C# page's Page_Load event handler fires. --Maybe this is an "order of operations" problem? At what point in the C# page's lifetime should a usercontrol's form be loaded? If anyone has any ideas or insight, I'd really appreciate it. Thanks in advance.

  Read the article

• Division by zero: Undefined Behavior or Implementation Defined in C and/or C++ ?

  - by SiegeX

  Regarding division by zero, the standards say: C99 6.5.5p5 - The result of the / operator is the quotient from the division of the first operand by the second; the result of the % operator is the remainder. In both operations, if the value of the second operand is zero, the behavior is undefined. C++03 5.6.4 - The binary / operator yields the quotient, and the binary % operator yields the remainder from the division of the first expression by the second. If the second operand of / or % is zero the behavior is undefined. If we were to take the above paragraphs at face value, the answer is clearly Undefined Behavior for both languages. However, if we look further down in the C99 standard we see the following paragraph which appears to be contradictory(1): C99 7.12p4 - The macro INFINITY expands to a constant expression of type float representing positive or unsigned infinity, if available; Do the standards have some sort of golden rule where Undefined Behavior cannot be superseded by a (potentially) contradictory statement? Barring that, I don't think it's unreasonable to conclude that if your implementation defines the INFINITY macro, division by zero is defined to be such. However, if your implementation does not define such a macro, the behavior is Undefined. I'm curious what the consensus on this matter for each of the two languages. Would the answer change if we are talking about integer division int i = 1 / 0 versus floating point division float i = 1.0 / 0.0 ? Note (1) The C++03 standard talks about the library which includes the INFINITY macro.

  Read the article

• Coding Practices which enable the compiler/optimizer to make a faster program.

  - by EvilTeach

  Many years ago, C compilers were not particularly smart. As a workaround K&R invented the register keyword, to hint to the compiler, that maybe it would be a good idea to keep this variable in an internal register. They also made the tertiary operator to help generate better code. As time passed, the compilers matured. They became very smart in that their flow analysis allowing them to make better decisions about what values to hold in registers than you could possibly do. The register keyword became unimportant. FORTRAN can be faster than C for some sorts of operations, due to alias issues. In theory with careful coding, one can get around this restriction to enable the optimizer to generate faster code. What coding practices are available that may enable the compiler/optimizer to generate faster code? Identifying the platform and compiler you use, would be appreciated. Why does the technique seem to work? Sample code is encouraged. Here is a related question [Edit] This question is not about the overall process to profile, and optimize. Assume that the program has been written correctly, compiled with full optimization, tested and put into production. There may be constructs in your code that prohibit the optimizer from doing the best job that it can. What can you do to refactor that will remove these prohibitions, and allow the optimizer to generate even faster code? [Edit] Offset related link

  Read the article

• New record may be written twice in clusterd index structure

  - by Cupidvogel

  As per the article at Microsoft, under the Test 1: INSERT Performance section, it is written that For the table with the clustered index, only a single write operation is required since the leaf nodes of the clustered index are data pages (as explained in the section Clustered Indexes and Heaps), whereas for the table with the nonclustered index, two write operations are required—one for the entry into the index B-tree and another for the insert of the data itself. I don't think that is necessarily true. Clustered Indexes are implemented through B+ tree structures, right? If you look at at this article, which gives a simple example of inserting into a B+ tree, we can see that when 8 is initially inserted, it is written only once, but then when 5 comes in, it is written to the root node as well (thus written twice, albeit not initially at the time of insertion). Also when 8 comes in next, it is written twice, once at the root and then at the leaf. So won't it be correct to say, that the number of rewrites in case of a clustered index is much less compared to a NIC structure (where it must occur every time), instead of saying that rewrite doesn't occur in CI at all?

  Read the article

• Domain model for an optional many-many relationship

  - by Greg

  Let's say I'm modeling phone numbers. I have one entity for PhoneNumber, and one for Person. There's a link table that expresses the link (if any) between the PhoneNumber and Person. The link table also has a field for DisplayOrder. When accessing my domain model, I have several Use Cases for viewing a Person. I can look at them without any PhoneNumber information. I can look at them for a specific PhoneNumber. I can look at them and all of their current (or past) PhoneNumbers. I'm trying to model Person, not only for the standard CRUD operations, but for the (un)assignment of PhoneNumbers to a Person. I'm having trouble expressing the relationship between the two, especially with respects to the DisplayOrder property. I can think of several solutions but I'm not sure of which (if any) would be best. A PhoneNumberPerson class that has a Person and PhoneNumber property (most closely resembles database design) A PhoneCarryingPerson class that inherits from Person and has a PhoneNumber property. A PhoneNumber and/or PhoneNumbers property on Person (and vis-a-versa, a Person property on PhoneNumber) What would be a good way to model this that makes sense from a domain model perspective? How do I avoid misplaced properties (DisplayOrder on Person) or conditionally populated properties?

  Read the article

• The CLR has been unable to transition from COM context [...] for 60 seconds

  - by BlueRaja The Green Unicorn

  I am getting this error on code that used to work. I have not changed the code. Here is the full error: The CLR has been unable to transition from COM context 0x3322d98 to COM context 0x3322f08 for 60 seconds. The thread that owns the destination context/apartment is most likely either doing a non pumping wait or processing a very long running operation without pumping Windows messages. This situation generally has a negative performance impact and may even lead to the application becoming non responsive or memory usage accumulating continually over time. To avoid this problem, all single threaded apartment (STA) threads should use pumping wait primitives (such as CoWaitForMultipleHandles) and routinely pump messages during long running operations. And here is the code that caused it: var openFileDialog1 = new System.Windows.Forms.OpenFileDialog(); openFileDialog1.DefaultExt = "mdb"; openFileDialog1.Filter = "Management Database (manage.mdb)|manage.mdb"; //Stalls indefinitely on the following line, then gives the CLR error //one minute later. The dialog never opens. if(openFileDialog1.ShowDialog() == DialogResult.OK) { .... } Yes, I am sure the dialog is not open in the background, and no, I don't have any explicit COM code or unmanaged marshalling or multithreading. I have no idea why the OpenFileDialog won't open - any ideas?

  Read the article

• Python optimization problem?

  - by user342079

  Alright, i had this homework recently (don't worry, i've already done it, but in c++) but I got curious how i could do it in python. The problem is about 2 light sources that emit light. I won't get into details tho. Here's the code (that I've managed to optimize a bit in the latter part): import math, array import numpy as np from PIL import Image size = (800,800) width, height = size s1x = width * 1./8 s1y = height * 1./8 s2x = width * 7./8 s2y = height * 7./8 r,g,b = (255,255,255) arr = np.zeros((width,height,3)) hy = math.hypot print 'computing distances (%s by %s)'%size, for i in xrange(width): if i%(width/10)==0: print i, if i%20==0: print '.', for j in xrange(height): d1 = hy(i-s1x,j-s1y) d2 = hy(i-s2x,j-s2y) arr[i][j] = abs(d1-d2) print '' arr2 = np.zeros((width,height,3),dtype="uint8") for ld in [200,116,100,84,68,52,36,20,8,4,2]: print 'now computing image for ld = '+str(ld) arr2 *= 0 arr2 += abs(arr%ld-ld/2)*(r,g,b)/(ld/2) print 'saving image...' ar2img = Image.fromarray(arr2) ar2img.save('ld'+str(ld).rjust(4,'0')+'.png') print 'saved as ld'+str(ld).rjust(4,'0')+'.png' I have managed to optimize most of it, but there's still a huge performance gap in the part with the 2 for-s, and I can't seem to think of a way to bypass that using common array operations... I'm open to suggestions :D

  Read the article

• Extracting noun+noun or (adj|noun)+noun from Text

  - by ssuhan

  I would like to query if it is possible to extract noun+noun or (adj|noun)+noun in R package openNLP?That is, I would like to use linguistic filtering to extract candidate noun phrases. Could you direct me how to do? Many thanks. Thanks for the responses. here is the code: library("openNLP") acq <- "Gulf Applied Technologies Inc said it sold its subsidiaries engaged in pipeline and terminal operations for 12.2 mln dlrs. The company said the sale is subject to certain post closing adjustments, which it did not explain. Reuter." acqTag <- tagPOS(acq) acqTagSplit = strsplit(acqTag," ") acqTagSplit qq = 0 tag = 0 for (i in 1:length(acqTagSplit[[1]])){ qq[i] <-strsplit(acqTagSplit[[1]][i],'/') tag[i] = qq[i][[1]][2] } index = 0 k = 0 for (i in 1:(length(acqTagSplit[[1]])-1)) { if ((tag[i] == "NN" && tag[i+1] == "NN") | (tag[i] == "NNS" && tag[i+1] == "NNS") | (tag[i] == "NNS" && tag[i+1] == "NN") | (tag[i] == "NN" && tag[i+1] == "NNS") | (tag[i] == "JJ" && tag[i+1] == "NN") | (tag[i] == "JJ" && tag[i+1] == "NNS")){ k = k +1 index[k] = i } } index Reader can refer index on acqTagSplit to do noun+noun or (adj|noun)+noun extractation. (The code is not optimum but work. If you have any idea, please let me know.) Furthermore, I still have a problem. Justeson and Katz (1995) proposed another linguistic filtering to extract candidate noun phrases: ((Adj|Noun)+|((Adj|Noun)(Noun-Prep)?)(Adj|Noun))Noun I cannot well understand its meaning, could someone do me a favor to explain it or transform such representation into R language

  Read the article

• How would I go about sharing variables in a C++ class with Lua?

  - by Nicholas Flynt

  I'm fairly new to Lua, I've been working on trying to implement Lua scripting for logic in a Game Engine I'm putting together. I've had no trouble so far getting Lua up and running through the engine, and I'm able to call Lua functions from C and C functions from Lua. The way the engine works now, each Object class contains a set of variables that the engine can quickly iterate over to draw or process for physics. While game objects all need to access and manipulate these variables in order for the Game Engine itself to see any changes, they are free to create their own variables, a Lua is exceedingly flexible about this so I don't forsee any issues. Anyway, currently the Game Engine side of things are sitting in C land, and I really want them to stay there for performance reasons. So in an ideal world, when spawning a new game object, I'd need to be able to give Lua read/write access to this standard set of variables as part of the Lua object's base class, which its game logic could then proceed to run wild with. So far, I'm keeping two separate tables of objects in place-- Lua spawns a new game object which adds itself to a numerically indexed global table of objects, and then proceeds to call a C++ function, which creates a new GameObject class and registers the Lua index (an int) with the class. So far so good, C++ functions can now see the Lua object and easily perform operations or call functions in Lua land using dostring. What I need to do now is take the C++ variables, part of the GameObject class, and expose them to Lua, and this is where google is failing me. I've encountered a very nice method here which details the process using tags, but I've read that this method is deprecated in favor of metatables. What is the ideal way to accomplish this? Is it worth the hassle of learning how to pass class definitions around using libBind or some equivalent method, or is there a simple way I can just register each variable (once, at spawn time) with the global lua object? What's the "current" best way to do this, as of Lua 5.1.4?

  Read the article

• Node & Redis: Crucial Design Issues in Production Mode

  - by Ali

  This question is a hybrid one, being both technical and system design related. I'm developing the backend of an application that will handle approx. 4K request per second. We are using Node.js being super fast and in terms of our database struction we are using MongoDB, with Redis being a layer between Node and MongoDB handling volatile operations. I'm quite stressed because we are expecting concurrent requests that we need to handle carefully and we are quite close to launch. However I do not believe I've applied the correct approach on redis. I have a class Student, and they constantly change stages(such as 'active', 'doing homework','in lesson' etc. Thus I created a Redis DB for each state. (1 for being 'active', 2 for being 'doing homework'). Above I have the structure of the 'active' students table; xa5p - JSON stringified object #1 pQrW - JSON stringified object #2 active_student_table - {{studentId:'xa5p'}, {studentId:'pQrW'}} Since there is no 'select all keys method' in Redis, I've been suggested to use a set such that when I run command 'smembers' I receive the keys and later on do 'get' for each id in order to find a specific user (lets say that age older than 15). I've been also suggested that in fact I used never use keys in production mode. My question is, no matter how 'conceptual' it is, what specific things I should avoid doing in Node & Redis in production stage?. Are they any issues related to my design? Students must be objects and I sure can list them in a list but I haven't done yet. Is it that crucial in production stage?

  Read the article

• Can the Subversion client (svn) derefence symbolic links as if they were files?

  - by Ryan B. Lynch

  I have a directory on a Linux system that mostly contains symlinks to files on a different filesystem. I'd like to add the directory to a Subversion repository, dereferencing the symlinks in the process (treating them as the files they point to, rather than links). Generally, I'd like to be able to handle any working-copy operations with this behavior, but the 'svn add' command is where it starts, I think. The SVN client utility doesn't appear to have any options related to symlink dereferencing in the working copy. I didn't find any references to this in the manual (http://svnbook.red-bean.com/en/1.5/index.html), either. I found a poster on the SVN users mailing list who asked the same question but never received an answer, here: http://markmail.org/message/ngchfnzlmm43yj7h (That poster ended up using hard links instead of symlinks. That technique is not an option, in my case, because the real underlying files reside on a separate filesystem.) I'm using Subversion v1.6.1 on Fedora 11. For what it's worth, I know that there are alternative tools/techniques that could help approximate this behavior, but which I have to discard for various reasons. I've already considered [and dust-binned] these possibilities: - a "union" mount, merging all of the the directories containing the real files, with the SVN working-copy directory as the "top" layer in the union; - copying/moving the real files to the same filesystem as the SVN working-copy, and using hardlinks instead of symlinks; - non-SVN version control systems. These were all neat ideas, and I'm sure they are good solutions to other problems, but they won't work given the constraints of this environment and situation.

  Read the article

• SQL Server INSERT, Scope_Identity() and physical writing to disc

  - by TheBlueSky

  Hello everyone, I have a stored procedure that does, among other stuff, some inserts in different table inside a loop. See the example below for clearer understanding: INSERT INTO T1 VALUES ('something') SET @MyID = Scope_Identity() ... some stuff go here INSERT INTO T2 VALUES (@MyID, 'something else') ... The rest of the procedure These two tables (T1 and T2) have an IDENTITY(1, 1) column in each one of them, let's call them ID1 and ID2; however, after running the procedure in our production database (very busy database) and having more than 6250 records in each table, I have noticed one incident where ID1 does not match ID2! Although normally for each record inserted in T1, there is record inserted in T2 and the identity column in both is incremented consistently. The "wrong" records were something like that: ID1 Col1 ---- --------- 4709 data-4709 4710 data-4710 ID2 ID1 Col1 ---- ---- --------- 4709 4710 data-4709 4710 4709 data-4710 Note the "inverted", ID1 in the second table. Knowing not that much about SQL Server underneath operations, I have put the following "theory", maybe someone can correct me on this. What I think is that because the loop is faster than physically writing to the table, and/or maybe some other thing delayed the writing process, the records were buffered. When it comes the time to write them, they were wrote in no particular order. Is that even possible if no, how to explain the above mentioned scenario? If yes, then I have another question to rise. What if the first insert (from the code above) got delayed? Doesn't that mean I won't get the correct IDENTITY to insert into the second table? If the answer of this is also yes, what can I do to insure the insertion in the two tables will happen in sequence with the correct IDENTITY? I appreciate any comment and information that help me understand this. Thanks in advance.

  Read the article

• ReaderWriterLockSlim and Pulse/Wait

  - by Jono

  Is there an equivalent of Monitor.Pulse and Monitor.Wait that I can use in conjunction with a ReaderWriterLockSlim? I have a class where I've encapsulated multi-threaded access to an underlying queue. To enqueue something, I acquire a lock that protects the underlying queue (and a couple of other objects) then add the item and Monitor.Pulse the locked object to signal that something was added to the queue. public void Enqueue(ITask task) { lock (mutex) { underlying.Enqueue(task); Monitor.Pulse(mutex); } } On the other end of the queue, I have a single background thread that continuously processes messages as they arrive on the queue. It uses Monitor.Wait when there are no items in the queue, to avoid unnecessary polling. (I consider this to be good design, but any flames (within reason) are welcome if they help me learn otherwise.) private void DequeueForProcessing(object state) { while (true) { ITask task; lock (mutex) { while (underlying.Count == 0) { Monitor.Wait(mutex); } task = underlying.Dequeue(); } Process(task); } } As more operations are added to this class (requiring read-only access to the lock protected underlying), someone suggested using ReaderWriterLockSlim. I've never used the class before, and assuming it can offer some performance benefit, I'm not against it, but only if I can keep the Pulse/Wait design.

  Read the article

• Using SMO to call Database.ExecuteNonQuery() concurrently?

  - by JimDaniel

  I have been banging my head against the wall trying to figure out how I can run update scripts concurrently against multiple databases in a single SQL Server instance using SMO. Our environments have an ever-increasing number of databases which need updating, and iterating through one at a time is becoming a problem (too slow). From what I understand SMO does not support concurrent operations, and my tests have bore that out. There seems to be shared memory at the Server object level, for things like DataReader context, keeps throwing exceptions such as "reader is already open." I apologize for not having the exact exceptions I am getting. I will try to get them and update this post. I am no expert on SMO and just feeling my way through to be honest. Not really sure I am approaching it the right way, but it's something that has to be done, or our productivity will slow to a crawl. So how would you guys do something like this? Am I using the wrong technology with SMO? All I am wanting to do is execute sql scripts against databases in a single sql server instance in parallel. Thanks for any help you can give, Daniel

  Read the article

< Previous Page | 128 129 130 131 132 133 134 135 136 137 138 139  | Next Page >