# Performance impact due to \_source storage **URL:** \ **Category:** Elasticsearch\ **Created:** [June 7, 2015, 7:56am UTC](https://discuss.elastic.co/t/performance-impact-due-to--source-storage/2081 "2015-06-07T07:56:02Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![mosiddi](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mosiddi/32/577_2.png) [@mosiddi](https://discuss.elastic.co/u/mosiddi)\ **Post date:** [June 7, 2015, 7:56am UTC](https://discuss.elastic.co/t/performance-impact-due-to--source-storage/2081/1 "2015-06-07T07:56:02Z")
If we store the \_source so that we can do partial update > [Partial Updates to Documents | Elasticsearch: The Definitive Guide [2.x] | Elastic](https://www.elastic.co/guide/en/elasticsearch/guide/current/partial-updates.html) Other than having a hit on disk space needed to sore the data, do we have any known query scenario where performance will be hit? ---
**Author:** ![nik9000](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nik9000/32/44947_2.png) [@nik9000](https://discuss.elastic.co/u/nik9000)\ **Post date:** [June 8, 2015, 10:29am UTC](https://discuss.elastic.co/t/performance-impact-due-to--source-storage/2081/2 "2015-06-08T10:29:56Z")
Typically storing source is the right way to go but if you frequently highlight or return small fields (\< 100KB) on documents that contain large fields (\> 2MB) you'll start to see decoding the source be a performance hit. On the other hand this is something that the Elasticsearch team is talking about working on so I expect that problem will disappear in a while. Its a bit of a complex issue but its a recognized one. ---
**Author:** ![mosiddi](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mosiddi/32/577_2.png) [@mosiddi](https://discuss.elastic.co/u/mosiddi)\ **Post date:** [June 8, 2015, 12:05pm UTC](https://discuss.elastic.co/t/performance-impact-due-to--source-storage/2081/3 "2015-06-08T12:05:33Z")
thanks @nik9000 ---
**Author:** ![mosiddi](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mosiddi/32/577_2.png) [@mosiddi](https://discuss.elastic.co/u/mosiddi)\ **Post date:** [July 3, 2015, 4:42pm UTC](https://discuss.elastic.co/t/performance-impact-due-to--source-storage/2081/4 "2015-07-03T16:42:45Z")
@nik9000 - Looks like I'm running into the issue you explained. My \_source is big in size and I'm using nested mapping. I've bunch of fields but I'm interested to retrieve only a few. One of the field to be retrieved is nested field. I tried setting store to true for nested field but looks like I'm running into this issue: [https://github.com/elastic/elasticsearch/issues/5245](https://github.com/elastic/elasticsearch/issues/5245) @johtani / @Martijn_van_Groninge - was this issue fixed? [[https://github.com/elastic/elasticsearch/issues/5245](https://github.com/elastic/elasticsearch/issues/5245)] ---
**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, 12:03am UTC](https://discuss.elastic.co/t/performance-impact-due-to--source-storage/2081/5 "2017-07-06T00:03:41Z")