locking

I have a problem regarding the behaviour of the pthread function pthread_rwlock_wrlock . The specification linked above states that when one thread has locked the lock for writing and the same thread locks it again, it results in undefined behaviour (I could actually observe this in that on x86 Linux calling this function is a noop and on PowerPC Linux it stalls the thread). The behaviour I need would be a read write lock that has the following characteristics: read-locking by a thread succeeds if: the lock is not held by any thread the lock is only read-locked by zero or more threads

I work with multethreading bug. Now I see that for some reason lock isn't executed even once but is locked. I have the next class: public sealed class Foo { private readonly object _lock = new object(); private static ulong _inCnt = 0; public void SomeMethod(ulong poo) { lock (_lock) { _inCnt++; ... [some code] } } } I paused all threads in the VS, inspected all of them and see that there is only one thread in the SomeMethod and it is waiting for lock (_lock) to be freed (_inCnt = 0) . I resumed threads, waited for a while, paused threads and see the same picture, the same (and only one)

I'd like to lock specified row(s) in my table exclusively, so no reads no updates allowed until the actual transaction completes. To do this, I've created a helper class in my database repository: public void PessimisticMyEntityHandler(Action<IEnumerable<MyEntity>> fieldUpdater, string sql, params object[] parameters) { using (var scope = new System.Transactions.TransactionScope()) { fieldUpdater(DbContext.Set<MyEntity>().SqlQuery(sql, parameters)); scope.Complete(); } } Here is my test code. Basicly I'm just starting two tasks and both of them tries to lock the row with the Id '1'. My guess

During the ASP.NET execution of my app, it seems SQL 2008 Express holds some lock, and I get Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding Maybe some of my query is not optimized. Visual Studio crashes with: Microsoft Visual Studio may be unstable now. It is recommended that you save all files and exit. I need to see what query is blocking my tables, but I have the Express version. How can I do? Thanks You can query against the sys.dm_tran_locks dynamic view to obtain this information. Go here on MSDN to lean more. exec sp_lock

Normally when I ask for a thread dump, the symptoms of a poorly performing system are easily explained; i.e. normally I would be able to see that a number of threads are clearly waiting on a monitor which has been acquired but not released by another. In this case, I have a lot of threads waiting for a monitor (0x965ad100), but none appears to have that monitor in the first place. The threads in question can be identified with this signature: waiting to lock <0x965ad100> (a uk.gov.dti.og.fox.ConAgent) I've tried Googling this, and all I seem to find are posts that discuss monitors that are

This is a small program that only i am writing and using. Now i am going to write code of all areas where i use the hashset that caused this problem I don't understand how this is possible. This item is being used only at MainWindow hsProxyList is a hashset HashSet<string> hsProxyList = new HashSet<string>(); the error happened at below iteration lock (hsProxyList) { int irRandomProxyNumber = GenerateRandomValue.GenerateRandomValueMin(hsProxyList.Count, 0); int irLocalCounter = 0; foreach (var vrProxy in hsProxyList) { if (irLocalCounter == irRandomProxyNumber) { srSelectedProxy = vrProxy;