# Potential memory overhead of the "Term Lookup" mechanism

**URL:** <https://discuss.elastic.co/t/potential-memory-overhead-of-the-term-lookup-mechanism/20159>\
**Category:** Elasticsearch\
**Created:** [October 9, 2014, 10:17am UTC](https://discuss.elastic.co/t/potential-memory-overhead-of-the-term-lookup-mechanism/20159 "2014-10-09T10:17:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Freddy\_Mallet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/freddy_mallet/32/1221_2.png) [@Freddy\_Mallet](https://discuss.elastic.co/u/Freddy_Mallet)\
**Post date:** [October 9, 2014, 10:17am UTC](https://discuss.elastic.co/t/potential-memory-overhead-of-the-term-lookup-mechanism/20159/1 "2014-10-09T10:17:17Z")

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Hi Guys,

We're about to use the "Term Lookup" mechanism  
([http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-terms-filter.html](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-terms-filter.html))  
to do a term filter potentially on a big amount of terms, let's say 5'000  
terms containing each of them 20 characters.

To design the documents everything is clear but before starting using this  
feature (which is a way to do a kind of minimalistic "join" between two  
indexes), we do have a controversial discussion internally about the  
potential memory overhead relating to the use of this mechanism. I just  
have the feeling that the overhead won't be so important but don't have any  
factual arguments.

Is there anyone knowing how to approximate the memory which might be  
consumed by this mechanism ?

Thanks

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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, 12:57am UTC](https://discuss.elastic.co/t/potential-memory-overhead-of-the-term-lookup-mechanism/20159/2 "2017-07-06T00:57:21Z")

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Closed on July 6, 2017, 12:57am UTC