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  • Problems with contenttypes when loading a fixture in Django

    - by gerdemb
    I am having trouble loading Django fixtures into my MySQL database because of contenttypes conflicts. First I tried dumping the data from only my app like this: ./manage.py dumpdata escola > fixture.json but I kept getting missing foreign key problems, because my app "escola" uses tables from other applications. I kept adding additional apps until I got to this: ./manage.py dumpdata contenttypes auth escola > fixture.json Now the problem is the following constraint violation when I try to load the data as a test fixture: IntegrityError: (1062, "Duplicate entry 'escola-t23aluno' for key 2") It seems the problem is that Django is trying to dynamically recreate contenttypes with different primary key values that conflict with the primary key values from the fixture. This appears to be the same as bug documented here: http://code.djangoproject.com/ticket/7052 The problem is that the recommended workaround is to dump the contenttypes app which I'm already doing!? What gives? If it makes any difference I do have some custom model permissions as documented here: http://docs.djangoproject.com/en/dev/ref/models/options/#permissions

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  • WCF Blocking problem with mutiple clients!!

    - by Marcel
    Hi I seem to have a blocking issue with WCF. Say I have two users and each have created their own instance of a class exposed on a WCF host using net.tcp with endpoint something like this "net.tcp://localhost:32000/SymHost/". The class is PerSession context and concurrency is reentrant. The class exposes two methods Alive() which return a bool of true straight away and an AliveWait which I inserted which does a Thread.Sleep for 4 seconds before returning true (testing purposes). Now client 1 calls AliveWait() during which time he is blocked which is fair enough but then if client 2 makes a call to Alive() on its own instance he has to wait until client 1's call is returned - this behaviour is not what I would have expected? I would have expected client 2 to carry on as if nothing has happened or is this to do with the fact that they both share the same endpoint? Can anyone explain what is going on and how I can make sure that client 2 can call its own instance uninterrupted? Any help much appreciated!

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  • deploying gwt web application on jetty

    - by Azhar
    Hi I am deploying my web application created in Gwt on the jetty. I have used mongodb as my database.After starting the server it starts deploying the weapp.war and gives following error - 694 [main] INFO org.mortbay.log - Extract /usr/share/jetty/webapps/myapp.war to /tmp/Jetty_0_0_0_0_8090_myapp.war__myapp__n6yltk/webapp 3567 [main] WARN org.mortbay.log - failed Startup: java.lang.LinkageError: loader constraint violation: loader (instance of org/mortbay/jetty/webapp/WebAppClassLoader) previously initiated loading for a different type with name "javax/management/MBeanServer" at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:634) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:277) at java.net.URLClassLoader.access$000(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:212) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:392) at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:363) at com.mongodb.DBPortPool$Holder.get(DBPortPool.java:58) at com.mongodb.DBTCPConnector._set(DBTCPConnector.java:458) at com.mongodb.DBTCPConnector.<init>(DBTCPConnector.java:46) at com.mongodb.Mongo.<init>(Mongo.java:137) at com.mongodb.Mongo.<init>(Mongo.java:123)

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  • Adobe Socket Policy File Server Problems

    - by Matt
    Has anyone been able to successfully implement a service to serve the required socket policy file to FlashPlayer? I am running the Python implementation of the service provided by Adobe at http://www.adobe.com/devnet/flashplayer/articles/socket_policy_files.html and using the following policy file: <?xml version="1.0" encoding="UTF-8"?> <cross-domain-policy> <site-control permitted-cross-domain-policies="master-only"/> <allow-access-from domain="*" to-ports="*" secure="false"/> </cross-domain-policy> and receiving this message from Flash: [SecurityErrorEvent type="securityError" bubbles=false cancelable=false eventPhase=2 text="Error #2048: Security sandbox violation: http://www.mapopolis.com/family/Tree.swf cannot load data from www.mapopolis.com:1900."] Thanks.

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  • JavaScript multithreading

    - by Krzysztof Hasinski
    I'm working on comparison for several different methods of implementing (real or fake) multithreading in JavaScript. As far as I know only webworkers and Google Gears WorkerPool can give you real threads (ie. spread across multiple processors with real parallel execution). I've found the following methods: switch between tasks using yield() use setInterval() (or other non-blocking function) with threads waiting one for another use Google Gears WorkerPool threads (with plugin) use html5 web workers I read related questions and found several variations of the above methods, but most of those questions are old, so there might be a few new ideas. I'm wondering - how else can you achieve multithreading in JavaScript? Any other important methods? UPDATE: As pointed out in comments what I really meant was concurrency. UPDATE 2: I found information that Silverlight + JScript supports multithreading, but I'm unable to verify this. UPDATE 3: Google deprecated Gears: http://code.google.com/apis/gears/api_workerpool.html

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  • Trim function in C, to trim in place (without returning the string)

    - by user364100
    I can't figure out what to do to make this work. Here's my code: char* testStr = " trim this "; char** pTestStr = &testStr; trim(pTestStr); int trim(char** pStr) { char* str = *pStr; while(isspace(*str)) { (*pStr)++; str++; } if(*str == 0) { return 0; } char *end = str + strlen(str) - 1; while(end > str && isspace(*end)) end--; *(end+1) = 0; return 0; } I get an access violation on *(end+1) = 0;, but I can't declare my testStr[] as such to avoid that, because I can't pass the pointers that way. Any ideas?

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  • Does DB2 have an "insert or update" statement?

    - by Mikael Eriksson
    From my code (Java) I want to ensure that a row exists in the database (DB2) after my code is executed. My code now does a select and if no result is returned it does an insert. I really don't like this code since it exposes me to concurrency issuses when running in a multi-threaded environment. What I would like to do is to put this logic in DB2 instead of in my Java code. Does DB2 have an "insert-or-update" statement? Or anything like it that I can use? For example: insertupdate into mytable values ('myid') Another way of doing it would probably be to allways do the insert and catch "SQL-code -803 primary key already exists", but I would like to avoid that if possible.

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  • getting detailed information about structured exceptions

    - by Martin
    My Visual C++ application is compiled with /EHA option, letting me catch structured exceptions (division by zero, access violation, etc). I then translate those exceptions to my own exception class using _set_se_translator(). My goal is to improve our logging of those types of exceptions. I can get the type of exception from the EXCEPTION_RECORD structure, and the exception address. I would like to be able to gather more information, like the source file/location where the exception is thrown, the call stack, etc. Is that possible? I do create an exception minidump on structured exceptions - is there a tool to automatically get the call stack from that?

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  • Using an EJB inside a JAX-RS resource class in RestEasy?

    - by Laird Nelson
    I would like to have the following kind of resource class work when deployed under RestEasy in JBoss 6: @Path("Something") public class Foo { @EJB private SomeService service @GET public Object frobnicate() { assert service != null; // JBoss blows up here return result; } } Two questions: It is a limitation of RestEasy, not of the Java EE specification, right, that RestEasy can't inject anything annotated with @EJB? What have people done to work around this limitation? My developers are about to surge forward with hard-coded JNDI lookups (e.g. context.lookup(someHardCodedNameHere)) because no one can find a workaround to this specification violation at the present time. I really want to avoid this. Lastly, I've looked at using CDI, but the story here isn't much better as RestEasy and CDI still aren't talking to each other. Thanks in advance for any pointers.

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  • Is it really wrong to version documents using CouchDB's default behaviour?

    - by Tomas Sedovic
    This is one of those "I know I shouldn't do this but it's oh so convenient." questions. Sorry about that. I plan to use CouchDB for storing a bunch of documents and keeping their entire revision history. CouchDB does the versioning automatically, but it is strongly discouraged for programmer's use: "You cannot rely on document revisions for any other purpose than concurrency control." From what I've found on the CouchDB wiki, the versions can get deleted either during compaction or during replication. As far as I can tell, Compaction must always be triggered manually and Replication occurs only when there's more than one database server. The question is: if I won't run compaction and will use only single database instance for my documents, can I just use CouchDB's document versioning and expect it to work? What other problems I might run into? E.g. does not running compaction hurt the performance or consume significantly more disk space (than if I did handle the versioning manually)?

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  • NerdDinner difficulties

    - by George
    Hello guys, I'm having a problem with the Create method of the NerdDinner tutorial, which is very good BTW. As you can see here http://nerddinnerbook.s3.amazonaws.com/Part5.htm in the Create method, he removed the ID field of the aspx page. I did that too, but I cannot add any dinners because I get a primary key violation. How is NerdDinner controlling the ids of each dinner? I revised the tutorial and could not see any references to identity fields on SQL database. I even created a method to get me the highest id in the table: public int GetHighestDinnerId() { int resultado = (from dinner in dataContext.Dinners select dinner.DinnerId).Max(); return resultado; } which does not work either. Any thoughts? Thank you

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  • Clojure lots of threads

    - by Timothy Baldridge
    I just got done watching Rick Hickey's "Clojure Concurrency" talk, and I have a few questions about threads. Let's say I have a situation with lots of Agents, let's say 10,000 of them running one machine. I'd rather not have 10,000 CPU threads running at once, but I don't want threads to be blocked by the actions of other threads. In this example I won't really be waiting for replies, instead each Agent will be sending a message or two, and then waiting until it gets a message. How would I structure a program like this without getting 10k OS threads which would probably end up slowing the system down.

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  • What Belongs to the Aggregate Root

    - by jlembke
    This is a practical Domain Driven Design question: Conceptually, I think I get Aggregate roots until I go to define one. I have an Employee entity, which has surfaced as an Aggregate root. In the Business, some employees can have work-related Violations logged against them: Employee-----*Violations Since not all Employees are subject to this, I would think that Violations would not be a part of the Employee Aggregate, correct? So when I want to work with Employees and their related violations, is this two separate Repository interactions by some Service? Lastly, when I add a Violation, is that method on the Employee Entity? Thanks for the help!

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  • Mongrel with Ruby 1.9.

    - by JussiR
    When starting the server, I get this strange error after updating to Ruby 1.9: " [BUG] cross-thread violation on rb_gc() ruby 1.8.6 (2008-08-11) [i386-mswin32] This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. " My mongrel version is 1.1.6, which should be compatible with Ruby 1.9. I also still have the Ruby 1.8.6 installation, so i assume that for some reason mongrel tries to access that and kills ruby? My rails version is 2.3.4, in case it matters.

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  • Why better isolation level means better performance in SQL Server

    - by Oleg Zhylin
    When measuring performance on my query I came up with a dependency between isolation level and elapsed time that was surprising to me READUNCOMMITTED - 409024 READCOMMITTED - 368021 REPEATABLEREAD - 358019 SERIALIZABLE - 348019 Left column is table hint, and the right column is elapsed time in microseconds (sys.dm_exec_query_stats.total_elapsed_time). Why better isolation level gives better performance? This is a development machine and no concurrency whatsoever happens. I would expect READUNCOMMITTED to be the fasted due to less locking overhead. Update: I did measure this with DBCC DROPCLEANBUFFERS DBCC FREEPROCCACHE issued and Profiler confirms there're no cache hits happening. Update2: The query in question is an OLAP one and we need to run it as fast as possible. Closing the production server from outside world to get the computation done is not out of question if this gives performance benefits.

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  • "No context-sensitive help installed" , "user32.dll" and "uxtheme.dll" AV errors on Delphi with no reason

    - by Javid
    This is very strange guys. I wrote a simple application. When I make my commands executed fast by moving mouse (event is on mouse move), I experience the following errors if I run my application without debugger (if I do, application just hangs and nothing happens): 1- "No context-sensitive help installed" however i haven't used help in my app. 2- Access violation errors from "uxtheme.dll" and "user32.dll" libraries! well, i think these errors happen when Windows Messages are sent quickly one after another. I came across these errors a while ago in a huge application. In both application I used SendMessage command, but what am i doing wrong? I'm now using Delphi 2010 Has anyone ever experienced this?!

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  • Mock Assertions on objects inside Parallel ForEach's???

    - by jacko
    Any idea how we can assert a mock object was called when it is being accessed inside Parallel.ForEach via a closure? I assume that because each invocation is on a different thread that Rhino Mocks loses track of the object? Pseudocode: var someStub = MockRepository.GenerateStub() Parallel.Foreach(collectionOfInts, anInt => someStub.DoSomething(anInt)) someStub.AssertWasCalled(s => s.DoSomething, Repeat.Five.Times) This test will return an expectation violation, expecting the stub to be called 5 times but being actually called 0 times. Any ideas how we can tell the lambdas to keep track of the thread-local stub object?

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  • Identity column SQL Server 2005 inserting same value twice

    - by DannykPowell
    I have a stored procedure that inserts into a table (where there is an identity column that is not the primary key- the PK is inserted initially using the date/time to generate a unique value). We then use SCOPEIDENTITY() to get the value inserted, then there is some logic to generate the primary key field value based on this value, which is then updated back to the table. In some situations the stored procedure is called simultaneously by more than one process, resulting in "Violation of PRIMARY KEY constraint..." errors. This would seem to indicate that the identity column is allowing the same number to be inserted for more than one record. First question- how is this possible? Second question- how to stop it...there's no error handling currently so I'm going to add some try/ catch logic- but would like to understand the problem fully to deal with properly

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  • the MVCC effect on migration from oracle to db2

    - by Ryan Fernandes
    I have a simple (actually simplified :) ) scenario that is possibly the cause for the headache I've been having for the last few days... My current application (that serves 100's of users) currently uses Oracle as the database. I have no stored procs (I wish actually). Now, I've been asked if the product will work if I migrate to IBM DB2 as the database. So, after taking Oracle for granted all this while.... and having re-read Tom's article on MVCC (Multiversion Concurrency Control) and going through this post stating that DB2 is not 'on the list' or 'just tip-toeing in the area' as it were... I know I can't be sure that the product will work with DB2 as is. Is there no hope.. or is there a nice disclaimer I could use.. ?

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  • Trouble getting Flash socket policy file to work.

    - by Alex
    Basically I'm using Flash to connect to a Java server. Despite my Java application replying to the , in the Flash debug log it lists (not sure about the order as there are lots): * Security Sandbox Violation * Connection to 192.168.1.86:4049 halted - not permitted from http://127.0.0.1:8888/Current/wander.swf Warning: Timeout on xmlsocket://192.168.1.86:4049 (at 3 seconds) while waiting for socket policy file. This should not cause any problems, but see http://www.adobe.com/go/strict_policy_files for an explanation. Error: Request for resource at xmlsocket://192.168.1.86:4049 by requestor from http://127.0.0.1:8888/Current/wander.swf is denied due to lack of policy file permissions. What I don't understand is, the server (port 4049) receives the request, outputs the policy file and then closes the connection, surely it shouldn't time out? The policy file I'm using is: <?xml version="1.0"?> <cross-domain-policy><allow-access-from domain="*" to-ports="*" /> </cross-domain-policy>

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  • Is there a SQL Server error numbers C# wrapper anyone knows of?

    - by Mr Grok
    I really want to do something useful when a PK violation occurs but I hate trapping error numbers... they just don't read right without comments (they're certainly not self documenting). I know I can find all the potential error numbers at SQL Server books online but I really want to be able to pass the error number to some helper class or look it up against a Dictionary of some sort rather than have non-descript err numbers everywhere. Has anyone got / seen any code anywhere that encapsulates the SQL Server Error numbers in this way as I don't want to re-invent the wheel (or I'm lazy maybe).

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  • Parsing Serialized JSON DataSet using Jquery

    - by Zachary Carter
    Hello all, and thanks for reading. I wrote a web service which is called through jsonp, and returns a .Net 3.5 DataSet which I then want to parse using jquery. It appears that the getJson() method is working fine as far as parsing the json goes. The following request - $.getJSON("http://localhost:80/ws.asmx/Example?format=json&callback=?", function(data) { alert(data.d); }); results in - {"Tables": [ { "Rows": [ { "CASE_TYP_CD": "M", "CASE_TYP_DESC": "MOVING VIOLATION", "AUTO_GENERATE": "Y", "CONFIDENTIAL_FLG": "N" }, { "CASE_TYP_CD": "T", "CASE_TYP_DESC": "TRUANCY/FAILURE TO ATTEND SCHOOL", "AUTO_GENERATE": "Y", "CONFIDENTIAL_FLG": "N" }, { "CASE_TYP_CD": "J", "CASE_TYP_DESC": "JUVENILE", "AUTO_GENERATE": "Y", "CONFIDENTIAL_FLG": "N" }... Well I'm kind of new at this whole json thing and I can't figure out how to gain access to the values held in the nodes. I was thinking it would be something like - $.each("CASE_TYP_CD", function() { //code goes here }); But that doesn't seem to be working. Could anyone help me out with this? Thanks in advance!

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  • What parallel programming model do you recommend today to take advantage of the manycore processors

    - by Doctor J
    If you were writing a new application from scratch today, and wanted it to scale to all the cores you could throw at it tomorrow, what parallel programming model/system/language/library would you choose? Why? I am particularly interested in answers along these axes: Programmer productivity / ease of use (can mortals successfully use it?) Target application domain (what problems is it (not) good at?) Concurrency style (does it support tasks, pipelines, data parallelism, messages...?) Maintainability / future-proofing (will anybody still be using it in 20 years?) Performance (how does it scale on what kinds of hardware?) I am being deliberately vauge on the nature of the application in anticipation of getting good general answers useful for a variety of applications.

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  • Java: Set<E> collection, where items are identified by its class

    - by mschayna
    I need Set collection, where its items will be identified by items class. Something like ReferenceIdentityMap from Appache Collections, but on class scope i.e. two different instances of same class must be identified as same in this collection. You know, it is a violation of equals()/hashCode() identity principle but in occasional use it makes sense. I have done this in simple class backing with Map<Class<? extends E>, E>, but due to simplicity it doesn't implement Set<E>. There may be a more elegant solution, decorator of any Set<E> would be great. Is there any implementation of such collection there (Apache/Google/something/... Collections)?

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  • net c# lock statement in data access layer

    - by Pedro Rivera
    I saw a code where they have the data access layer like this: public class CustomerDA{ private static readonly object _sync = new object(); private static readonly CustomerDA _mutex = new CustomerDA(); private CustomerDA(){ } public CustomerDA GetInstance(){ lock(_sync){ return _mutex; } } public DataSet GetCustomers(){ //database SELECT //return a DataSet } public int UpdateCustomer(some parameters){ //update some user } } public class CustomerBO{ public DataSet GetCustomers(){ //some bussiness logic return CustomerDA.GetInstance().GetCustomers(); } } I was using it, but start thinking... "and what if had to build a facebook like application where there are hundreds of thousands of concurrent users? would I be blocking each user from doing his things until the previous user ends his database stuff? and for the Update method, is it useful to LOCK THREADS in the app when database engines already manage concurrency at database server level?" Then I started to think about moving the lock to the GetCustomers and UpdateCustomer methods, but think again: "is it useful at all?"

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