# Simulate index API slow

**URL:** <https://discuss.elastic.co/t/simulate-index-api-slow/340973>\
**Category:** Elasticsearch\
**Created:** [August 17, 2023, 7:02am UTC](https://discuss.elastic.co/t/simulate-index-api-slow/340973 "2023-08-17T07:02:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![franck.valentin](https://avatars.discourse-cdn.com/v4/letter/f/d2c977/32.png) [@franck.valentin](https://discuss.elastic.co/u/franck.valentin)\
**Post date:** [August 17, 2023, 7:02am UTC](https://discuss.elastic.co/t/simulate-index-api-slow/340973/1 "2023-08-17T07:02:17Z")

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Hi,

I experience performance issues when calling the simulate index API on 7.17 (via the Java method SimulateIndexTemplateRequest() or `/_index_template/_simulate_index/`).  
Our ES installation runs on a Kubernetes cluster that can handle hundreds of indexings and searches concurrently without issues but a query like:  
`curl -X POST "http://<HOST>/_index_template/_simulate_index/<MY_INDEX>` takes up to 30 seconds to reply.  
We have around 20 different index templates. Half of them have around 5 patterns but the other half has around 100 ones. Would this kind of configuration be the reason?

The patterns are all quite similar. Here is a snippet of what we define in the templates

```auto
  "coll-eo_eum_dat_0101-*",
    "coll-eo_eum_dat_0341-*",
    "coll-eo_eum_dat_0533-*",
    "coll-eo_eum_dat_0534-*",
    "coll-eo_eum_dat_0576-*",
    "coll-eo_eum_dat_0579-*",
    "coll-eo_eum_dat_0590-*",
    "coll-eo_eum*_dat_0281-*",
    "coll-eo_eum*_dat_0282-*",

```

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<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:** [September 14, 2023, 7:02am UTC](https://discuss.elastic.co/t/simulate-index-api-slow/340973/2 "2023-09-14T07:02:58Z")

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