# Do sharding & flush hot threads indicate slow indexing?

**URL:** <https://discuss.elastic.co/t/do-sharding-flush-hot-threads-indicate-slow-indexing/214663>\
**Category:** Elasticsearch\
**Created:** [January 10, 2020, 8:50pm UTC](https://discuss.elastic.co/t/do-sharding-flush-hot-threads-indicate-slow-indexing/214663 "2020-01-10T20:50:43Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![viniciof](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/viniciof/32/53454_2.png) [@viniciof](https://discuss.elastic.co/u/viniciof)\
**Post date:** [January 10, 2020, 8:50pm UTC](https://discuss.elastic.co/t/do-sharding-flush-hot-threads-indicate-slow-indexing/214663/1 "2020-01-10T20:50:44Z")

</div>

Hello everyone,

I notice in my hot threads that it's spending a lot of time in write related sections of code. Also, I'm experiencing slower indexing rate than usual (45% decrease)

Here's the output: [https://gist.github.com/vinicioflores/fef2cd267224b1532c933eed57b4831c](https://gist.github.com/vinicioflores/fef2cd267224b1532c933eed57b4831c)

Please help,

Regards,

---

<div class="post-metadata">

**Author:** ![spinscale](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/spinscale/32/25011_2.png) [@spinscale](https://discuss.elastic.co/u/spinscale)\
**Post date:** [January 13, 2020, 1:52pm UTC](https://discuss.elastic.co/t/do-sharding-flush-hot-threads-indicate-slow-indexing/214663/2 "2020-01-13T13:52:13Z")

</div>

Hey

Are you running on a slower disk? Is it possible that you are by accident limiting write speeds, so that merging blocks indexing to not write too much data so that merging cannot keep up?

--Alex

---

<div class="post-metadata">

**Author:** ![viniciof](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/viniciof/32/53454_2.png) [@viniciof](https://discuss.elastic.co/u/viniciof)\
**Post date:** [January 15, 2020, 4:35pm UTC](https://discuss.elastic.co/t/do-sharding-flush-hot-threads-indicate-slow-indexing/214663/3 "2020-01-15T16:35:38Z")

</div>

How would you advice me to check this from ES cluster ? Any metric I can monitor to find out

---

<div class="post-metadata">

**Author:** ![viniciof](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/viniciof/32/53454_2.png) [@viniciof](https://discuss.elastic.co/u/viniciof)\
**Post date:** [January 20, 2020, 3:37pm UTC](https://discuss.elastic.co/t/do-sharding-flush-hot-threads-indicate-slow-indexing/214663/4 "2020-01-20T15:37:42Z")

</div>

Here's my hot threads output, please help:

> <https://gist.github.com/vinicioflores/9bf1c130625b5e39a519a4882ad4b92a>

I notice that in most of my data nodes, it invests a lot of time in stuck in this method:

**org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:672)**

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [February 17, 2020, 3:37pm UTC](https://discuss.elastic.co/t/do-sharding-flush-hot-threads-indicate-slow-indexing/214663/5 "2020-02-17T15:37:56Z")

</div>

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.