This post is older than a year. Consider some information might not be accurate anymore.
Used: elasticsearch v6.2.4
Elasticsearch has common thread defaults for bulk requests. If you need to tune or gap certain problems, you can change the thread and thread pool size settings in
elasticsearch.yml. In general it is not recommended to tweak anything! Use it at your own risk!
thread_pool API to check current settings.
host name min max queue queue_size alpha bulk 32 32 0 200 beta bulk 32 32 0 200 gamma bulk 32 32 0 200
elasticsearch.yml the pool size:
thread_pool: bulk: queue_size: 500
Perform a rolling restart and you will see:
host name min max queue queue_size alpha bulk 32 32 0 500 beta bulk 32 32 0 500 gamma bulk 32 32 0 500