# Estimating Filter Cache Needs **URL:** \ **Category:** Elasticsearch\ **Created:** [May 24, 2015, 1:43pm UTC](https://discuss.elastic.co/t/estimating-filter-cache-needs/23679 "2015-05-24T13:43:02Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![msukmanowsky](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/msukmanowsky/32/44771_2.png) [@msukmanowsky](https://discuss.elastic.co/u/msukmanowsky)\ **Post date:** [May 24, 2015, 1:43pm UTC](https://discuss.elastic.co/t/estimating-filter-cache-needs/23679/1 "2015-05-24T13:43:02Z")
Hey all, Is there an easy way (even if not entirely accurate) to estimate the size of an individual filter in the filter cache if we know the approximate number of documents the index holds? Realize it's a bit tricky as filter cache is node-level, not index-level by default. If it were straight non-sparse bitset then a filter would be n-bits in size: 1B documents = 1B bits = 125MB but I'm guessing ES tries to use a more clever implementation of a bitset. Thanks! Mike -- Mike Sukmanowsky Aspiring Digital Carpenter _p_: +1 (416) 953-4248 _e_: [mike.sukmanowsky@gmail.com](mailto:mike.sukmanowsky@gmail.com) facebook [http://facebook.com/mike.sukmanowsky](http://facebook.com/mike.sukmanowsky) | twitter [http://twitter.com/msukmanowsky](http://twitter.com/msukmanowsky) | LinkedIn [http://www.linkedin.com/profile/view?id=10897143](http://www.linkedin.com/profile/view?id=10897143) | github [https://github.com/msukmanowsky](https://github.com/msukmanowsky) ## -- Please update your bookmarks! We have moved to [https://discuss.elastic.co/](https://discuss.elastic.co/) You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/CAOH6cu7OyEVd2VQ2\_ZzxJMhE3kshEuBXYRyoN0%2BSPJguxbHdCg%40mail.gmail.com](https://groups.google.com/d/msgid/elasticsearch/CAOH6cu7OyEVd2VQ2_ZzxJMhE3kshEuBXYRyoN0%2BSPJguxbHdCg%40mail.gmail.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**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, 12:12am UTC](https://discuss.elastic.co/t/estimating-filter-cache-needs/23679/2 "2017-07-06T00:12:11Z")