I found a bug report of a very similar case (JDK-8143380) which was closed as “Not an Issue” by Stuart Marks: This is a class initialization deadlock. The test program’s main thread executes the class static initializer, which sets the initialization in-progress flag for the class; this flag remains set until the static initializer completes. … Read more
Maybe a simple bank situation. class Account { double balance; void withdraw(double amount){ balance -= amount; } void deposit(double amount){ balance += amount; } void transfer(Account from, Account to, double amount){ sync(from); sync(to); from.withdraw(amount); to.deposit(amount); release(to); release(from); } } Obviously, should there be two threads which attempt to run transfer(a, b) and transfer(b, a) at … Read more
The Microsft SQL Server-specific error code for a deadlock is 1205 so you’d need to handle the SqlException and check for that. So, e.g. if for all other types of SqlException you want the bubble the exception up: catch (SqlException ex) { if (ex.Number == 1205) { // Deadlock } else throw; } Or, using … Read more
Lock is a questionable idea in JS which is intended to be threadless and not needing concurrency protection. You’re looking to combine calls on deferred execution. The pattern I follow for this is the use of callbacks. Something like this: var functionLock = false; var functionCallbacks = []; var lockingFunction = function (callback) { if … Read more
Take a look at this example, Stephen has a clear answer for you: So this is what happens, starting with the top-level method (Button1_Click for UI / MyController.Get for ASP.NET): The top-level method calls GetJsonAsync (within the UI/ASP.NET context). GetJsonAsync starts the REST request by calling HttpClient.GetStringAsync (still within the context). GetStringAsync returns an uncompleted … Read more
Q1:Could the time it takes for a transaction to execute make the associated process more likely to be flagged as a deadlock victim. No. The SELECT is the victim because it had only read data, therefore the transaction has a lower cost associated with it so is chosen as the victim: By default, the Database … Read more
No, not as long as you are locking on the same object. The recursive code effectively already has the lock and so can continue unhindered. lock(object) {…} is shorthand for using the Monitor class. As Marc points out, Monitor allows re-entrancy, so repeated attempts to lock on an object on which the current thread already … Read more
Acquiring a value via an async method: var result = Task.Run(() => asyncGetValue()).Result; Syncronously calling an async method Task.Run( () => asyncMethod()).Wait(); No deadlock issues will occur due to the use of Task.Run.
A lock occurs when multiple processes try to access the same resource at the same time. One process loses out and must wait for the other to finish. A deadlock occurs when the waiting process is still holding on to another resource that the first needs before it can finish. So, an example: Resource A … Read more
The difference between a recursive and non-recursive mutex has to do with ownership. In the case of a recursive mutex, the kernel has to keep track of the thread who actually obtained the mutex the first time around so that it can detect the difference between recursion vs. a different thread that should block instead. … Read more