Alexander Reelsen 2ebb21f108 Watcher: Reduce threads on non-data nodes (elastic/x-pack-elasticsearch#3932)
The watcher thread pool is scaled by the number of CPUs and has by
default up to 5x the number of cores. This is needed because we assumme
I/O based waiting workloads for watcher. However if the node is not a
data node, there will not be any execution of watches with the exception
of a user calling the execute watch API on that node.

This means, we can get away with just one thread, so that there is no
need for the JVM to manage more threads on master/client or ingest only
nodes.

Original commit: elastic/x-pack-elasticsearch@b5899401d3
2018-02-23 09:16:32 +01:00
..
2018-01-18 16:34:25 -08:00