# Performance of post\_filter
**URL:** https://discuss.elastic.co/t/performance-of-post-filter/202752
**Category:** Elasticsearch
**Created:** [October 9, 2019, 2:03am UTC](https://discuss.elastic.co/t/performance-of-post-filter/202752 "2019-10-09T02:03:29Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@hkazuakey](https://discuss.elastic.co/u/hkazuakey)
#### Post date: [October 9, 2019, 2:03am UTC](https://discuss.elastic.co/t/performance-of-post-filter/202752/1 "2019-10-09T02:03:29Z")
Hello,
I have a question about performance of post\_filter. According to the legacy document (definitive guide), performance consideration is required and it should be used only in combination with aggregations. However, the latest reference document has never mentioned about performance thing. Is it still be required to consider?
I understand that the post\_filter is only applied to the hits. So, if the doc set is very large, filter is better since the doc set could be smaller. But our usual doc set is not so large, which has total 12M docs and 400K docs are associated with a problematic query, which shows bad query performance.
Could you please let me know if you have any comments or/and suggestions.
Best,
Kazuaki
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 6, 2019, 2:03am UTC](https://discuss.elastic.co/t/performance-of-post-filter/202752/2 "2019-11-06T02:03:35Z")
This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.