[infinispan-dev] race condition in AsyncStore

Hi Galder, This is following an email sent this morning on an infinit loop in AsyncTest. I've found what was[1] causing the infinite loop. Here it is (see comments in the code): Let's say we do put(k1, v1) and put(k1, v2) in this order void run0() throws InterruptedException { if (trace) log.trace("Checking for modifications"); boolean unlock = false; try { acquireLock(write); unlock = true; swap = state; state = newStateMap(); } finally { if (unlock) write.unlock(); } //thread ONE comes here and is processing (k1, v1); it releases the write lock. Immediately, thread TWO acquires write lock, and takes (k1,v2) from the store into its swap. // the race condition happens when thread TWO executes (i.e. persists) before thread one, and as a result in the store the final value persisted is v1 (not v2). // This is known to be an async (i.e. best effort store), so this situation might be considered as normal behavior. Still, I think this induces unwanted errors/behavior. // A possible solution is to only release the WL after put(swap). if (trace) log.trace("About to insert the swap: " + swap); int size = swap.size(); if (size == 0) awaitNotEmpty(); else decrementAndGet(size); if (trace) log.trace("Calling put(List) with {0} modifications", size); put(swap); } Cheers, Mircea [1] I say 'was' because I modified the test to fail (intermittently) rather than hang