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  • TransactionScope Prematurely Completed

    - by Chris
    I have a block of code that runs within a TransactionScope and within this block of code I make several calls to the DB. Selects, Updates, Creates, and Deletes, the whole gamut. When I execute my delete I execute it using an extension method of the SqlCommand that will automatically resubmit the query if it deadlocks as this query could potentially hit a deadlock. I believe the problem occurs when a deadlock is hit and the function tries to resubmit the query. This is the error I receive: The transaction associated with the current connection has completed but has not been disposed. The transaction must be disposed before the connection can be used to execute SQL statements. This is the simple code that executes the query (all of the code below executes within the using of the TransactionScope): using (sqlCommand.Connection = new SqlConnection(ConnectionStrings.App)) { sqlCommand.Connection.Open(); sqlCommand.ExecuteNonQueryWithDeadlockHandling(); } Here is the extension method that resubmits the deadlocked query: public static class SqlCommandExtender { private const int DEADLOCK_ERROR = 1205; private const int MAXIMUM_DEADLOCK_RETRIES = 5; private const int SLEEP_INCREMENT = 100; public static void ExecuteNonQueryWithDeadlockHandling(this SqlCommand sqlCommand) { int count = 0; SqlException deadlockException = null; do { if (count > 0) Thread.Sleep(count * SLEEP_INCREMENT); deadlockException = ExecuteNonQuery(sqlCommand); count++; } while (deadlockException != null && count < MAXIMUM_DEADLOCK_RETRIES); if (deadlockException != null) throw deadlockException; } private static SqlException ExecuteNonQuery(SqlCommand sqlCommand) { try { sqlCommand.ExecuteNonQuery(); } catch (SqlException exception) { if (exception.Number == DEADLOCK_ERROR) return exception; throw; } return null; } } The error occurs on the line that executes the nonquery: sqlCommand.ExecuteNonQuery();

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  • dynamically created controls and responding to control events

    - by Dirk
    I'm working on an ASP.NET project in which the vast majority of the forms are generated dynamically at run time (form definitions are stored in a DB for customizability). Therefore, I have to dynamically create and add my controls to the Page every time OnLoad fires, regardless of IsPostBack. This has been working just fine and .NET takes care of managing ViewState for these controls. protected override void OnLoad(EventArgs e) { base.OnLoad(e); RenderDynamicControls() } private void RenderDynamicControls(){ //1. call service layer to retrieve form definition //2. create and add controls to page container } I have a new requirement in which if a user clicks on a given button (this button is created at design time) the page should be re-rendered in a slightly different way. So in addition to the code that executes in OnLoad (i.e. RenderDynamicControls()), I have this code: protected void MyButton_Click(object sender, EventArgs e) { RenderDynamicControlsALittleDifferently() } private void RenderDynamicControlsALittleDifferently() (){ //1. clear all controls from the page container added in RenderDynamicControls() //2. call service layer to retrieve form definition //3. create and add controls to page container } My question is, is this really the only way to accomplish what I'm after? It seems beyond hacky to effectively render the form twice simply to respond to a button click. I gather from my research that this is simply how the page-lifecycle works in ASP.NET: Namely, that OnLoad must fire on every Postback before child events are invoked. Still, it's worthwhile to check with the SO community before having to drink the kool-aid. On a related note, once I get this feature completed, I'm planning on throwing an UpdatePanel on the page to perform the page updates via Ajax. Any code/advice that make that transition easier would be much appreciated. Thanks

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  • Re-tweets and replies with JTwitter

    - by Samuh
    I have not used Twitter enough to become familiar with its terminology or the way it works, so please help me in understanding the problem I have at hand. I am getting last 20 status updates posted by some Twitter user via RSS feed, the feed XML is parsed and the statuses are displayed in a ListView. Which means that I have the original tweet in a String variable(row of ListView). When I click a ListView item, I get the option of "Re-tweeting" and "post reply". As, I understand it, when re-tweeting I will have to just update my *status* as: RT @orig-poster <original tweet> and when posting a reply I will have to just update my status as: @orig-poster <my tweet> I skimmed through the JavaDocs of the Jwitter library(Twitter class) and found a setStatus(String) method. I dont think I will have to make use of retweet() or reply() functions of the Twitter class in JTwitter library. Is my understanding correct? Please correct me if I am wrong here or missing anything. Thanks!

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  • Storing an object to use in multiple classes

    - by Aaron Sanders
    I am wondering the best way to store an object in memory that is used in a lot of classes throughout an application. Let me set up my problem for you: We have multiple databases, 1 per customer. We also have a master table and each row is detailed information about the databases such as database name, server IP it's located and a few config settings. I have an application that loops through those multiple databases and runs some updates on them. The settings I mentioned above are updated each loop iteration into memory. The application then runs through series of processes that include multiple classes using this data. The data never changes during the processes, only during the loop iteration. The variables are related to a customer, so I have them stored in a customer class. I suppose I could make all of the members shared or should I use a singleton for the customer class? I've never actually used a singleton, only read they are good in this type of situation. Are there better solutions to this type of scenario? Also, I could have plans for this application to be multithreaded later. Sorry if this is confusing. If you have questions, let me know and I will answer them. Thanks for your help.

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  • Multiple threads modifying a collection in Java??

    - by posdef
    Hi, The project I am working on requires a whole bunch of queries towards a database. In principle there are two types of queries I am using: read from excel file, check for a couple of parameters and do a query for hits in the database. These hits are then registered as a series of custom classes. Any hit may (and most likely will) occur more than once so this part of the code checks and updates the occurrence in a custom list implementation that extends ArrayList. for each hit found, do a detail query and parse the output, so that the classes created in (I) get detailed info. I figured I would use multiple threads to optimize time-wise. However I can't really come up with a good way to solve the problem that occurs with the collection these items are stored in. To elaborate a little bit; throughout the execution objects are supposed to be modified by both (I) and (II). I deliberately didn't c/p any code, as it would be big chunks of code to make any sense.. I hope it make some sense with the description above. Thanks,

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  • Call Webservice using Javascript

    - by ajithperuva
    I am trying to call a webservice using javascript.But it shows an error like selectSingleNode() is not a method.I am trying it in mozilla firefox.Which is perfectly working in explorer when i change XMLHttpRequest to ActiveXObject.here i am adding my source code which i am tried in firefox. // Web Service functionality // Global vars var xmlDoc = null; var _serviceCallback = null; // Calls web service, web service url and parms, and callback function or null must be provided. // Callback function receives a true or false based on success of call to host function callWebService(url, callback) { _serviceCallback = callback; if(xmlDoc == null) { // xmlDoc = new XMLHttpRequest(); xmlDoc = new XMLHttpRequest(); } xmlDoc.onreadystatechange = stateChange; //callback for readystate xmlDoc.async = true; //do background processing //xmlDoc.load(url); xmlDoc.open('GET', url); xmlDoc.send(); //var doc= xmlDoc.responseXML; } // Updates readystate by callback function stateChange() { if (xmlDoc.readyState == 4) { var err = xmlDoc.parseError; var result = false; var nd; if(err.errorCode == 0) { nd = xmlDoc.selectSingleNode("//envelope/date_time"); if(nd.text != "") result = true; } // perform callback if provided if(_serviceCallback != null) _serviceCallback(result, nd == null ? "" : nd.text); } } // Callback supplied to XMLHttpRequest call function callbackTest(result, data) { obj = document.getElementById("txtOuput"); if(result) obj.value = "Success " + data; else obj.value = "Web Service Call Failed"; } Please help me...Already which kill my 8 more hours...

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  • PayPal integration woes: PDT hangs on return to site

    - by Tom
    Hi, I'm implementing PayPal IPN & PDT. After some headache & time at the sandbox, IPN is working well and PDT returns the correct $_GET data. The implementation is as follows: Pass user ID in form to PayPal User buys product and triggers IPN which updates database for given user ID PDT returns transaction ID when user returns to site The return page says "please wait" and repeat-Ajax-checks for the transaction status User is redirected to success/failure page Everything works well, EXCEPT that when using the PayPal ready PHP code for PDT to do a return POST, the page hangs. PayPal waits for a response and the user never gets back to my site. I'm not getting a fail status, just nothing. The funny thing is that once the unknown error occurs, my test domain becomes unresponsive for a short period. The code (PHP): https://www.paypal.com/us/cgi-bin/webscr?cmd=p/xcl/rec/pdt-code-outside If I comment out the POST back, it all works fine. I'm able to pin down the problem to once the code enters the while{} loop. Unfortunately, I'm not experienced enough to write a replacement from scratch for the PayPal code, so would really appreciate any ideas on what might be wrong. The POST back goes to ssl://www.sandbox.paypal.com, and I'm using button code and an authorisation token that have all been created via a sandbox test account. Thanks in advance.

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  • ASP.net file operations delay

    - by mtranda
    Ok, so here's the problem: I'm reading the stream from a FileUpload control, reading in chunks of n bytes and writing the array in a loop until I reach the stream's end. Now the reason I do this is because I need to check several things while the upload is still going on (rather than doing a Save(); which does the whole thing in one go). Here's the problem: when doing this from the local machine, I can see the file just fine as it's uploading and its size increases (had to add a Sleep(); clause in the loop to actually get to see the file being written). However, when I upload the file from a remote machine, I don't get to see it until the the file has completed uploading. Also, I've added another call to write the progress to a text file as the progress is going on, and I get the same thing. Local: the file updates as the upload goes on, remote: the token file only appears after the upload's done (which is somewhat useless since I need it while the upload's still happening). Is there some sort of security setting in (or ASP.net) that maybe saves files in a temporary location for remote machines as opposed to the local machine and then moves them to the specified destination? I would liken this with ASP.net displaying error messages when browsing from the local machine (even on the public hostname) as opposed to the generic compilation error page/generic exception page that is shown when browsing from a remote machine (and customErrors are not off) Any clues on this? Thanks in advance.

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  • How to create refresh statements for TableAdapter objects in Visual Studio?

    - by Mark Wilkins
    I am working on developing an ADO.NET data provider and an associated DDEX provider. I am unable to convince the Visual Studio TableAdapater Configuration Wizard to generate SQL statements to refresh the data table after inserts and updates. It generates the insert and delete statements but will not produce the select statements to do the refresh. The functionality referred to can be accessed by dropping a table from the Server Explorer (inside Visual Studio) onto a DataSet (e.g., DataSet1.xsd). It creates a TableAdapter object and configures SELECT, UPDATE, DELETE, and INSERT statements. If you right click on the TableAdapter object, the context menu has a “Configure” option that starts the “TableAdapter Configuration Wizard”. The first dialog of that wizard has an Advanced Options button, which leads to an option titled “Refresh the data table”. When used with SQL Server tables, that option causes a statement of the form “select field1, field2, …” to be added on to the end of the commands for the TableAdapter’s InsertCommand and UpdateCommand. Do you have any idea what type property or interface might need to be exposed from the DDEX provider (or maybe the ADO.NET data provider) in order to make Visual Studio add those refresh statements to the update/insert commands? The MSDN documentation for the Advanced SQL Generation Options Dialog Box has a note stating, “Refreshing the data table is only supported on databases that support batching of SQL statements.” This seems to imply that a .NET data provider might need to expose some property indicating such behavior is supported. But I cannot find it. Any ideas?

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  • Drawing only part of a

    - by Ben Reeves
    ..Continued on from my previous question I have a 320*480 RGB565 framebuffer which I wish to draw using OpenGL ES 1.0 on the iPhone. - (void)setupView { glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_CROP_RECT_OES, (int[4]){0, 0, 480, 320}); glEnable(GL_TEXTURE_2D); } // Updates the OpenGL view when the timer fires - (void)drawView { // Make sure that you are drawing to the current context [EAGLContext setCurrentContext:context]; //Get the 320*480 buffer const int8_t * frameBuf = [source getNextBuffer]; //Create enough storage for a 512x512 power of 2 texture int8_t lBuf[2*512*512]; memcpy (lBuf, frameBuf, 320*480*2); //Upload the texture glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 512, 512, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, lBuf); //Draw it glDrawTexiOES(0, 0, 1, 480, 320); [context presentRenderbuffer:GL_RENDERBUFFER_OES]; } If I produce the original texture in 512*512 the output is cropped incorrectly but other than that looks fine. However using the require output size of 320*480 everything is distorted and messed up. I'm pretty sure it's the way I'm copying the framebuffer into the new 512*512 buffer. I have tried this routine int8_t lBuf[512][512][2]; const char * frameDataP = frameData; for (int ii = 0; ii < 480; ++ii) { memcpy(lBuf[ii], frameDataP, 320); frameDataP += 320; } Which is better, but the width appears to be stretched and the height is messed up. Any help appreciated.

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  • Can you have a Dynamic Data Field which consists of a list of fields?

    - by Telos
    This is a purely theoretical question (at least until I start trying to implement it) but here goes. I wrote a web form a long time ago which has a configurable section for getting information. Basically for some customers there are no fields, for other customers there are up to 20 fields. I got it working by dynamically creating the fields at just the right time in the page lifecycle and going through a lot of headaches. 2 years later, I need to make some pretty big updates to this web form and there are some nifty new technologies. I've worked with ASP.NET Dynamic Data just a bit and, well, I half-crazed plan just occurred to me: The Ticket object has a one-to-many relationship to ExtendedField, we'll call that relationship Fields for brevity. Using that, the idea would be to create a FieldTemplate that dynamically generated the list of fields and displayed it. The big questions here would probably be: 1) Can a single field template resolve to multiple web controls without breaking things? 2) Can dynamic data handle updating/inserting multiple rows in such a fashion? 3) There was a third question I had a few minutes ago, but coworkers interrupted me and I forgot. So now the third question is: what is the third question? So basically, does this sound like it could work or am I missing a better/more obvious solution?

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  • C# Windows Service doesn't seem to like privatePath

    - by SauerC
    I wrote a C# Windows Service to handle task scheduling for our application. I'm trying to move the "business rules" assemblies into a bin subdirectory of the scheduling application to make it easier for us to do updates (stop service, delete all files in bin folder, replace with new ones, start service). I added <runtime> <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> <probing privatePath="bin;"/> </assemblyBinding> </runtime> to the service's app config and it works fine if the service is run as a console application. Problem is when the service is run as a windows service it doesn't work. It appears that when windows runs the service the app config file gets read properly but then the service is executed as if it was in c:\windows\system32 and not the actually EXE location and that gums up the works. We've got a lot of assemblies so I really don't want to use the GAC or <codeBase>. Is it possible to have the EXE change it's base directory back to where it should be when it's run as a service?

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  • How to represent and insert into an ordered list in SQL?

    - by Travis
    I want to represent the list "hi", "hello", "goodbye", "good day", "howdy" (with that order), in a SQL table: pk | i | val ------------ 1 | 0 | hi 0 | 2 | hello 2 | 3 | goodbye 3 | 4 | good day 5 | 6 | howdy 'pk' is the primary key column. Disregard its values. 'i' is the "index" that defines that order of the values in the 'val' column. It is only used to establish the order and the values are otherwise unimportant. The problem I'm having is with inserting values into the list while maintaining the order. For example, if I want to insert "hey" and I want it to appear between "hello" and "goodbye", then I have to shift the 'i' values of "goodbye" and "good day" (but preferably not "howdy") to make room for the new entry. So, is there a standard SQL pattern to do the shift operation, but only shift the elements that are necessary? (Note that a simple "UPDATE table SET i=i+1 WHERE i=3" doesn't work, because it violates the uniqueness constraint on 'i', and also it updates the "howdy" row unnecessarily.) Or, is there a better way to represent the ordered list? I suppose you could make 'i' a floating point value and choose values between, but then you have to have a separate rebalancing operation when no such value exists. Or, is there some standard algorithm for generating string values between arbitrary other strings, if I were to make 'i' a varchar? Or should I just represent it as a linked list? I was avoiding that because I'd like to also be able to do a SELECT .. ORDER BY to get all the elements in order.

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  • How do I Data-Bind dual DateTimePicker to a single DateTime object

    - by S.C. Madsen
    Hi, I have a simple form, with two DateTimePicker-controls: One for date, and one for time. The thing is these two controls are supposed to represent a single point in time. Hence I would like to "Bind" them to a single DateTime property on my form (for simplicity). I did the following: // Start is a DateTime property on the form _StartDate.DataBindings.Add("Value", this, "Start"); _StartTime.DataBindings.Add("Value", this, "Start"); But hooking into "ValueChanged" event, yields mixed results... Sometimes I get exactly what I want, sometimes the updates of the property are "sluggish". I figured this way of splitting into two DateTimePicker's was fairly common. So how to do it? Update: There is possibly multiple questions in there: How do I bind a DateTimePicker (Format: Date) to a DateTime Property on a form? Then, how do I bind yet another DateTimePicker (Format: Time) to the same property? I'm using Visual Studio Express 2008 (.NET 3.5), and I seemingly get ValueChanged events from the DateTimePickers before the value is changed?

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  • Can any linux API or tool watch for any change in any folder below e.g. /SharedRoot or do I have to

    - by Simon B.
    I have a folder with ~10 000 subfolders. Can any linux API or tool watch for any change in any folder below e.g. /SharedRoot or do I have to setup inotify for each folder? (i.e. I loose if I want to do this for 10k+ folders). I guess yes, since I've already seen examples of this inefficient method, for instance http://twistedmatrix.com/trac/browser/trunk/twisted/internet/inotify.py?rev=28866#L345 My problem: I need to keep folders time-sorted with most recently active "project" up top. When a file changes, each folder above that file should update its last-modified timestamp to match the file. Delays are ok. Opening a file (typically MS Excel) and closing again, its file date can jump up and then down again. For this reason I need to wait until after a file is closed, then queue the folder of that file for checking, and only a while later do I go and look for the newest file in its folder, since the filedate of the triggering file could already be back-dated to its original timestamp by Excel or similar programs. Also in case several files from same folder are used/created, it makes sense to buffer timestamping of that folders' parents to at least get a bunch of updates collapsed into one delayed update. I'm looking for a linux solution. I have some code that can be run on a windows server, most of the queing functionality is here: http://github.com/sesam/FolderdateFollowsFiles/blob/master/FolderdateFollowsFiles/Follower.vb Available API:s The relative of inotify on windows, ReadDirectoryChangesW, can watch a folder and its whole subtree; see bWatchSubtree on http://msdn.microsoft.com/en-us/library/aa365465(VS.85).aspx Samba? Patching samba source is a possibility, but perhaps there are already hooks available? Other possibilities, like client side (various windows versions) and spying on file activities in order to update folders recursively?

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  • Oracle command hangs when using view for "WHILE x IN..." subquery

    - by Calvin Fisher
    I'm working on a web service that fetches data from an oracle data source in chunks and passes it back to an indexing/search tool in XML format. I'm the C#/.NET guy, and am kind of fuzzy on parts of Oracle. Our Oracle team gave us the following script to run, and it works well: SELECT ROWID, [columns] FROM [table] WHERE ROWID IN ( SELECT ROWID FROM ( SELECT ROWID FROM [table] WHERE ROWID > '[previous_batch_last_rowid]' ORDER BY ROWID ) WHERE ROWNUM <= 10000 ) ORDER BY ROWID 10,000 rows is an arbitrary but reasonable chunk size and ROWID is sufficiently unique for our purposes to use as a UID since each indexing run hits only one table at a time. Bracketed values are filled in programmatically by the web service. Now we're going to start adding views to the indexing, each of which will union a few separate tables. Since ROWID would no longer function as a unique identifier, they added a column to the views (VIEW_UNIQUE_ID) that concatenates the ROWIDs from the component tables to construct a UID for each union. But this script does not work, even though it follows the same form as the previous one: SELECT VIEW_UNIQUE_ID, [columns] FROM [view] WHERE VIEW_UNIQUE_ID IN ( SELECT VIEW_UNIQUE_ID FROM ( SELECT VIEW_UNIQUE_ID FROM [view] WHERE ROWID > '[previous_batch_last_view_unique_id]' ORDER BY VIEW_UNIQUE_ID ) WHERE ROWNUM <= 10000 ) ORDER BY VIEW_UNIQUE_ID It hangs indefinitely with no response from the Oracle server. I've waited 20+ minutes and the SQLTools dialog box indicating a running query remains the same, with no progress or updates. I've tested each subquery independently and each works fine and takes a very short amount of time (<= 1 second), so the view itself is sound. But as soon as the inner two SELECT queries are added with "WHERE VIEW_UNIQUE_ID IN...", it hangs. Why doesn't this query work for views? In what important way are they not interchangeable here?

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  • .NET Remoting Connecting to Wrong Host

    - by Dark Falcon
    I have an application I wrote which has been running well for 4 years. Yesterday they moved all their servers around and installed about 60 pending Windows updates, and now it is broken. The application makes use of remoting to update some information on another server (10.0.5.230), but when I try to create my remote object, I get the following exception: Note that it is trying to connect to 127.0.0.1, not the proper server. The server (10.0.5.230) is listening on port 9091 as it should. This same error is happening on all three terminal servers where this application is installed. Here is the code which registers the remoted object: public static void RegisterClient() { string lServer; RegistryKey lKey = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Shoreline Teleworks\\ShoreWare Client"); if (lKey == null) throw new InvalidOperationException("Could not find Shoretel Call Manager"); object lVal = lKey.GetValue("Server"); if (lVal == null) throw new InvalidOperationException("Shoretel Call Manager did not specify a server name"); lServer = lVal.ToString(); IDictionary props = new Hashtable(); props["port"] = 0; string s = System.Guid.NewGuid().ToString(); props["name"] = s; ChannelServices.RegisterChannel(new TcpClientChannel(props, null), false); RemotingConfiguration.RegisterActivatedClientType(typeof(UpdateClient), "tcp://" + lServer + ":" + S_REMOTING_PORT + "/"); RemotingConfiguration.RegisterActivatedClientType(typeof(Playback), "tcp://" + lServer + ":" + S_REMOTING_PORT + "/"); } Here is the code which calls the remoted object: UpdateClient lUpdater = new UpdateClient(Settings.CurrentSettings.Extension.ToString()); lUpdater.SetAgentState(false); I have verified that the following URI is passed to RegisterActivatedClientType: "tcp://10.0.5.230:9091/" Why does this application try to connect to the wrong server?

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  • Bidirectional replication update record problem

    - by Mirek
    Hi, I would like to present you my problem related to SQL Server 2005 bidirectional replication. What do I need? My teamleader wants to solve one of our problems using bidirectional replication between two databases, each used by different application. One application creates records in table A, changes should replicate to second database into a copy of table A. When data on second server are changed, then those changes have to be propagated back to the first server. I am trying to achieve bidirectional transactional replication between two databases on one server, which is running SQL Server 2005. I have manage to set this up using scripts, established 2 publications and 2 read only subscriptions with loopback detection. Distributtion database is created, publishment on both databases is enabled. Distributor and publisher are up. We are using some rules to control, which records will be replicated, so we need to call our custom stored procedures during replication. So, articles are set to use update, insert and delete custom stored procedures. So far so good, but? Everything works fine, changes are replicating, until updates are done on both tables simultaneously or before changes are replicated (and that takes about 3-6 seconds). Both records then end up with different values. UPDATE db1.dbo.TestTable SET Col = 4 WHERE ID = 1 UPDATE db2.dbo.TestTable SET Col = 5 WHERE ID = 1 results to: db1.dbo.TestTable COL = 5 db2.dbo.TestTable COL = 4 But we want to have last change winning replication. Please, is there a way to solve my problem? How can I ensure same values in both records? Or is there easier solution than this kind of replication? I can provide sample replication script which I am using. I am looking forward for you ideas, Mirek

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  • Is it possible to store pointers in shared memory without using offsets?

    - by Joseph Garvin
    When using shared memory, each process may mmap the shared region into a different area of their address space. This means that when storing pointers within the shared region, you need to store them as offsets of the start of the shared region. Unfortunately, this complicates use of atomic instructions (e.g. if you're trying to write a lock free algorithm). For example, say you have a bunch of reference counted nodes in shared memory, created by a single writer. The writer periodically atomically updates a pointer 'p' to point to a valid node with positive reference count. Readers want to atomically write to 'p' because it points to the beginning of a node (a struct) whose first element is a reference count. Since p always points to a valid node, incrementing the ref count is safe, and makes it safe to dereference 'p' and access other members. However, this all only works when everything is in the same address space. If the nodes and the 'p' pointer are stored in shared memory, then clients suffer a race condition: x = read p y = x + offset Increment refcount at y During step 2, p may change and x may no longer point to a valid node. The only workaround I can think of is somehow forcing all processes to agree on where to map the shared memory, so that real pointers rather than offsets can be stored in the mmap'd region. Is there any way to do that? I see MAP_FIXED in the mmap documentation, but I don't know how I could pick an address that would be safe.

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  • First site going live real soon. Last minute questions

    - by user156814
    I am really close to finishing up on a project that I've been working on. I have done websites before, but never on my own and never a site that involved user generated data. I have been reading up on things that should be considered before you go live and I have some questions. 1) Staging... (Deploying updates without affecting users). I'm not really sure what this would entail, since I'm sure that any type of update would affect users in some way. Does this mean some type of temporary downtime for every update? can somebody please explain this and a solution to this as well. 2) Limits... I'm using the Kohana framework and I'm using the Auth module for logging users in. I was wondering if this already has some type of limit (on login attempts) built in, and if not, what would be the best way to implement this. (save attempts in database, cookie, etc.). If this is not whats meant by limits, can somebody elaborate. 3) Caching... Like I said, this is my first site built around user content. Considering that, should I cache it? 4) Back Ups... How often should I backup my (MySQL) database, and how should I back it up (MySQL export?). The site is currently up, yet not finished, if anybody wants to look at it and see if something pops out to you that should be looked at/fixed. Clashing Thoughts. If there is anything else I overlooked, thats not already in the list linked to above, please let me know. Thanks.

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  • suggestions for declarative GUI programming in Java

    - by Jason S
    I wonder if there are any suggestions for declarative GUI programming in Java. (I abhor visual-based GUI creator/editor software, but am getting a little tired of manually instantiating JPanels and Boxes and JLabels and JLists etc.) That's my overall question, but I have two specific questions for approaches I'm thinking of taking: JavaFX: is there an example somewhere of a realistic GUI display (e.g. not circles and rectangles, but listboxes and buttons and labels and the like) in JavaFX, which can interface with a Java sourcefile that accesses and updates various elements? Plain Old Swing with something to parse XUL-ish XML: has anyone invented a declarative syntax (like XUL) for XML for use with Java Swing? I suppose it wouldn't be hard to do, to create some code based on STaX which reads an XML file, instantiates a hierarchy of Swing elements, and makes the hierarchy accessible through some kind of object model. But I'd rather use something that's well-known and documented and tested than to try to invent such a thing myself. JGoodies Forms -- not exactly declarative, but kinda close & I've had good luck with JGoodies Binding. But their syntax for Form Layout seems kinda cryptic. edit: lots of great answers here! (& I added #3 above) I'd be especially grateful for hearing any experiences any of you have had with using one of these frameworks for real-world applications. p.s. I did try a few google searches ("java gui declarative"), just didn't quite know what to look for.

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  • Temporary storage for keeping data between program iterations?

    - by mr.b
    I am working on an application that works like this: It fetches data from many sources, resulting in pool of about 500,000-1,500,000 records (depends on time/day) Data is parsed Part of data is processed in a way to compare it to pre-existing data (read from database), calculations are made, and stored in database. Resulting dataset that has to be stored in database is, however, much smaller in size (compared to original data set), and ranges from 5,000-50,000 records. This process almost always updates existing data, perhaps adds few more records. Then, data from step 2 should be kept somehow, somewhere, so that next time data is fetched, there is a data set which can be used to perform calculations, without touching pre-existing data in database. I should point out that this data can be lost, it's not irreplaceable (key information can be read from database if needed), but it would speed up the process next time. Application components can (and will be) run off different computers (in the same network), so storage has to be reachable from multiple hosts. I have considered using memcached, but I'm not quite sure should I do so, because one record is usually no smaller than 200 bytes, and if I have 1,500,000 records, I guess that it would amount to over 300 MB of memcached cache... But that doesn't seem scalable to me - what if data was 5x that amount? If it were to consume 1-2 GB of cache only to keep data in between iterations (which could easily happen)? So, the question is: which temporary storage mechanism would be most suitable for this kind of processing? I haven't considered using mysql temporary tables, as I'm not sure if they can persist between sessions, and be used by other hosts in network... Any other suggestion? Something I should consider?

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  • binding nested json object value to a form field

    - by Jack
    I am building a dynamic form to edit data in a json object. First, if something like this exists let me know. I would rather not build it but I have searched many times for a tool and have found only tree like structures that require entering quotes. I would be happy to treat all values as strings. This edit functionality is for end users so it needs to be easy an not intimidating. So far I have code that generates nested tables to represent a json object. For each value I display a form field. I would like to bind the form field to the associated nested json value. If I could store a reference to the json value I would build an array of references to each value in a json object tree. I have not found a way to do that with javascript. My last resort approach will be to traverse the table after edits are made. I would rather have dynamic updates but a single submit would be better than nothing. Any ideas? // the json in files nests only a few levels. Here is the format of a simple case, { "researcherid_id":{ "id_key":"researcherid_id", "description":"Use to retrieve bibliometric data", "url_template" :[ { "name": "Author Detail", "url": "http://www.researcherid.com/rid/${key}" } ] } } $.get('file.json',make_json_form); function make_json_form(response) { dataset = $.secureEvalJSON(response); // iterate through the object and generate form field for string values. } // Then after the form is edited I want to display the raw updated json (then I want to save it but that is for another thread) // now I iterate through the form and construct the json object // I would rather have the dataset object var updated on focus out after each edit. function show_json(form_id){ var r = {}; var el = document.getElementById(form_id); table_to_json(r,el,null); $('body').html(formattedJSON(r)); }

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  • PHP script not automatically updating when moved to another server

    - by user32007
    A friend built a ranking system on his site and I am trying to host in on mine via WordPress and Go Daddy. It updates for him but when I load it to my site, it works for 6 hours, but as soon as the reload is supposed to occur, it errors and I get a 500 timeout error. His page is at: jeremynoeljohnson .com/yakezieclub My page is currently at http://sweatingthebigstuff.com/yakezieclub but when you ?reload=1 it will give the error. Any idea why this might be happening? Any settings that I might need to change? Here is the top of the index.php file. I'm not sure which part of any of it is messing up. I literally uploaded the same code as him. Here's the reload part: $cachefile = "rankings.html"; $daycachefile = "rankings_history.xml"; $cachetime = (60 * 60) * 6; // every 6 hours, the cache refreshes $daycachetime = (60 * 60) * 24; // every 24 hours, the history will be written to // - or whenever the page is requested after 24 hours has passed $writenewdata = false; if (!empty($_GET['reload'])) { if ($_GET['reload']== 1) { $cachetime = 1; } } if (!empty($_GET['reloadhistory'])) { if ($_GET['reloadhistory'] == 1) { $daycachetime = 1; $cachetime = 1; } } if (file_exists($daycachefile) && (time() - $daycachetime < filemtime($daycachefile))) { // Do nothing } else { $writenewdata = true; $cachetime = 1; } // Serve from the cache if it is younger than $cachetime if (file_exists($cachefile) && (time() - $cachetime < filemtime($cachefile))) { include($cachefile); echo "<!-- Cached ".date('jS F Y H:i', filemtime($cachefile))." -->"; exit; } ob_start(); // start the output buffer ?>

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  • How to have a where clause on an insert or an update in Linq to Sql?

    - by Kelsey
    I am trying to convert the following stored proc to a LinqToSql call (this is a simplied version of the SQL): INSERT INTO [MyTable] ([Name], [Value]) SELECT @name, @value WHERE NOT EXISTS(SELECT [Value] FROM [MyTable] WHERE [Value] = @value) The DB does not have a constraint on the field that is getting checked for so in this specific case the check needs to be made manually. Also there are many items constantly being inserted as well so I need to make sure that when this specific insert happens there is no dupe of the value field. My first hunch is to do the following: using (TransactionScope scope = new TransactionScope()) { if (Context.MyTables.SingleOrDefault(t => t.Value == in.Value) != null) { MyLinqModels.MyTable t = new MyLinqModels.MyTable() { Name = in.Name, Value = in.Value }; // Do some stuff in the transaction scope.Complete(); } } This is the first time I have really run into this scenario so I want to make sure I am going about it the right way. Does this seem correct or can anyone suggest a better way of going about it without having two seperate calls? Edit: I am running into a similar issue with an update: UPDATE [AnotherTable] SET [Code] = @code WHERE [ID] = @id AND [Code] IS NULL How would I do the same check with Linqtosql? I assume I need to do a get and then set all the values and submit but what if someone updates [Code] to something other than null from the time I do the get to when the update executes? Same problem as the insert...

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