metamx/druid — pull request #820 by drcrallen (2014-11-04 04:59:20+00:00)
Title: Update the ThreadPoolTaskRunner to use thread priorities

* Defaults the thread priority to java.util.Thread.NORM_PRIORITY in io.druid.indexing.common.task.AbstractTask
* Each exec service has its own Task Factory which is assigned a priority for spawned task. Therefore each priority class has a unique exec service