To find out whether it had any positive performance impact, I am trying with turning OFF speculative execution. Surprisingly, the job starts to fail in reduce phase with OOM errors when I disable speculative execution for both map and reduce tasks. Has anybody noticed similar behavior? Is there a way to find out how many tasks were speculatively executed when speculative execution is enabled?
I am trying with a 64GB Terasort run with 8-node cluster. Thanks, -Shrinivas
