# Overhead of \_source field in searches **URL:** \ **Category:** Elasticsearch\ **Created:** [September 9, 2014, 5:15am UTC](https://discuss.elastic.co/t/overhead-of--source-field-in-searches/19672 "2014-09-09T05:15:59Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![ElasticSearch\_Users\_](https://avatars.discourse-cdn.com/v4/letter/e/b4bc9f/32.png) [@ElasticSearch\_Users\_](https://discuss.elastic.co/u/ElasticSearch_Users_)\ **Post date:** [September 9, 2014, 5:15am UTC](https://discuss.elastic.co/t/overhead-of--source-field-in-searches/19672/1 "2014-09-09T05:15:59Z")
Hi, Will having \_source enabled for my documents put any kind of performance overhead or increase latency or memory consumption for searches that do not necessarily return the \_source field. I am not interested in the \_source field for returning during search, but the only purpose for \_source field for me is to update the document at a later point in time. If there is no overhead in maintaining the extra data due to the \_source field, either during indexing or searching, I will be okay to use it. However, I am not sure whether having \_source enabled will put a memory/IO strain during searching even though I do not return \_source as an output field. Thanks, Sandeep -- 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/e7649b9b-dca0-4af3-8f66-5e6f718dc9fc%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/e7649b9b-dca0-4af3-8f66-5e6f718dc9fc%40googlegroups.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**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:** [September 9, 2014, 12:17pm UTC](https://discuss.elastic.co/t/overhead-of--source-field-in-searches/19672/2 "2014-09-09T12:17:16Z")
\_source is not loaded unless it is needed. So the overhead should be very low. On Sep 9, 2014 1:16 AM, "'Sandeep Ramesh Khanzode' via elasticsearch" \< [elasticsearch@googlegroups.com](mailto:elasticsearch@googlegroups.com)\> wrote: > Hi, > > Will having \_source enabled for my documents put any kind of performance > overhead or increase latency or memory consumption for searches that do not > necessarily return the \_source field. I am not interested in the \_source > field for returning during search, but the only purpose for \_source field > for me is to update the document at a later point in time. If there is no > overhead in maintaining the extra data due to the \_source field, either > during indexing or searching, I will be okay to use it. However, I am not > sure whether having \_source enabled will put a memory/IO strain during > searching even though I do not return \_source as an output field. > > Thanks, > Sandeep > > -- > 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/e7649b9b-dca0-4af3-8f66-5e6f718dc9fc%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/e7649b9b-dca0-4af3-8f66-5e6f718dc9fc%40googlegroups.com) > [https://groups.google.com/d/msgid/elasticsearch/e7649b9b-dca0-4af3-8f66-5e6f718dc9fc%40googlegroups.com?utm\_medium=email&utm\_source=footer](https://groups.google.com/d/msgid/elasticsearch/e7649b9b-dca0-4af3-8f66-5e6f718dc9fc%40googlegroups.com?utm_medium=email&utm_source=footer) > . > For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). -- 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/CAPmjWd23pVfW-PVBhE\_Ovy\_CmvcpcuWGirxwgqmYbMn0rYD-wA%40mail.gmail.com](https://groups.google.com/d/msgid/elasticsearch/CAPmjWd23pVfW-PVBhE_Ovy_CmvcpcuWGirxwgqmYbMn0rYD-wA%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, 1:03am UTC](https://discuss.elastic.co/t/overhead-of--source-field-in-searches/19672/3 "2017-07-06T01:03:45Z")