How to check number of threads used for indexing in Elasticsearch?

[suvarna]

Hi

My system having 28 cores and 112 cpus.

How to check the number of threads used for indexing in Elasticsearch to enable the parallelism.

How to check the number of threads used for merging in Elaticsearch.

Please let me know the same.

[DavidTurner]

You can see statistics about thread usage in the nodes stats API. For instance, this will tell you how many write threads there are on each node:

GET /_nodes/stats?filter_path=nodes.*.thread_pool.write.threads

I do not think these stats include merge threads, because these do not belong to a thread pool. There is a setting to limit the maximum number of merge threads.

[suvarna]

Thanks for info.

curl -X GET "localhost:9200/_nodes/stats?filter_path=nodes.*.thread_pool.write.threads"

This gives me result as
{"nodes":{"knlA8wEDRq26cpfcQgh_6Q":{"thread_pool":{"write":{"threads":112}}}}}

Is there any possibility to increase the thread_pool with write threads more than 112 to increase the performance. (If yes what is the parameter )

Can you please let me know where to configure the "index.merge.scheduler.max_thread_count" (is it in elasicsearch.yml?)

[DavidTurner]

@suvarna

Is there any possibility to increase the thread_pool with write threads more than 112 to increase the performance. (If yes what is the parameter )

You can increase it to 113 but I doubt it'll help.

@suvarna

Can you please let me know where to configure the "index.merge.scheduler.max_thread_count" (is it in elasicsearch.yml?)

This is a per-index setting so you set it when creating the index or through the update indices settings API. Again I doubt it'll help, and it might even make things worse.