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!
Use the thread_pool API to check current settings.
GET _cat/thread_pool?h=host,name,min,max,queue,queue_size&v&s=name
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
Change in 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
