# DateHistogram Aggregation over indices split by month **URL:** \ **Category:** Elasticsearch\ **Created:** [March 23, 2019, 7:45am UTC](https://discuss.elastic.co/t/datehistogram-aggregation-over-indices-split-by-month/173580 "2019-03-23T07:45:27Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![arvinds94](https://avatars.discourse-cdn.com/v4/letter/a/e0b2c6/32.png) [@arvinds94](https://discuss.elastic.co/u/arvinds94)\ **Post date:** [March 23, 2019, 7:45am UTC](https://discuss.elastic.co/t/datehistogram-aggregation-over-indices-split-by-month/173580/1 "2019-03-23T07:45:28Z")
I do know that ElasticSearch can query across multiple indices when specified, but will it aggregate results that fall into the same bucket but were found in different indices. An example to clarify: A 7 day aggregation starting on the 25 of January. The first bucket in this example would contain data from both the index for the month of January and from the index for the month of Feb. Will it correctly aggregate the results into the bucket and is there a performance hit in doing this? Thanks, Arvind ---
**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\ **Post date:** [March 23, 2019, 7:55am UTC](https://discuss.elastic.co/t/datehistogram-aggregation-over-indices-split-by-month/173580/2 "2019-03-23T07:55:09Z")
Yes, that is not a problem. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [April 20, 2019, 7:55am UTC](https://discuss.elastic.co/t/datehistogram-aggregation-over-indices-split-by-month/173580/3 "2019-04-20T07:55:17Z")
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