elasticsearch/elasticsearch — pull request #5818 by s1monw (2014-04-15 13:25:12+00:00)
Title: Switch back to ConcurrentMergeScheduler

Load tests showed that SerialMS has problems to keep up with
the merges under high load. We should switch back to CMS
until we have a better story to balance merge
threads / efforts across shards on a single node.

Closes #5817