Keith Wiley wrote: > However, it is also not run in any concurrent fashion except > w.r.t. to the JVM itself. For example, my map task doesn't > make parallel calls through JNI to the native code on concurrent > threads at the Java level, nor does the native code itself spawn > any threads (like I said, it isn't even compiled with pthreads).
Is speculative execution enabled? > So, the question is, in the scenario I have described, is there > any reason to suspect that the cause of my problems is some > sort of thread trampling between the native code and something > else in the surrounding environment (the JVM or something like > that), especially in the context of the surrounding Hadoop > infrastructure? It doesn't really make any sense to me, but > I'm running out of ideas. I don't see any obvious possibilities except speculative execution, and even that would depend on how the shared library was written. Does it contain any global or static variables? If so, it's almost certainly not thread-safe (unless, say, a global variable were basically write- only and advisory only, e.g., used only in an error message or a summary message at the end). No other ideas. Greg
