# Query performance

**URL:** <https://discuss.elastic.co/t/query-performance/17525>\
**Category:** Elasticsearch\
**Created:** [May 15, 2014, 1:44am UTC](https://discuss.elastic.co/t/query-performance/17525 "2014-05-15T01:44:24Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![slushi](https://avatars.discourse-cdn.com/v4/letter/s/3e96dc/32.png) [@slushi](https://discuss.elastic.co/u/slushi)\
**Post date:** [May 15, 2014, 1:44am UTC](https://discuss.elastic.co/t/query-performance/17525/1 "2014-05-15T01:44:24Z")

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I am currently trying to improve/understand my query performance. The  
queries do a full text search, perform a sort, and utilize a terms filter.  
My understanding is the sort will use the field data cache and the filter  
uses the filter cache. Sometimes searches return in a few hundred  
milliseconds, other times it takes multiple seconds. The cluster runs on 4  
nodes and continuously indexes new documents.

What is the best way to understand why some queries take significantly  
longer? My guess is that it has to do with the state of the caches on the  
particular node(s) that the query executes on, but is there a way to verify  
this? It seems I can get an explain plan of the query, but not a breakdown  
of the timings spent in the filter/query/sort operations?

I was thinking of trying to change the terms filter execution option to  
fielddata, but the filter is on a fairly long string terms. My  
understanding that field data usage is mostly proportional to the number of  
unique values of the field in the index rather than the number of  
documents. Is this correct?

As documents are continuously being indexed, a warmer to load the sort  
field into the field data cache would also make sense? I was also reading  
this[http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/fielddata-formats.html#\_fielddata\_loading](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/fielddata-formats.html#_fielddata_loading)in the documentation concerning field data loading, but I didn't quite  
understand it. Is "category" an example of a field in the index? Overall  
load on the cluster is low, but I am wondering what is the impact of  
indexing and querying at the same time.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 1:29am UTC](https://discuss.elastic.co/t/query-performance/17525/2 "2017-07-06T01:29:17Z")

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Closed on July 6, 2017, 1:29am UTC