# What does Elasticsearch do when multiple indices share the same alias?

**URL:** <https://discuss.elastic.co/t/what-does-elasticsearch-do-when-multiple-indices-share-the-same-alias/38126>\
**Category:** Elasticsearch\
**Created:** [December 29, 2015, 8:44pm UTC](https://discuss.elastic.co/t/what-does-elasticsearch-do-when-multiple-indices-share-the-same-alias/38126 "2015-12-29T20:44:31Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Aisaac08](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/aisaac08/32/6903_2.png) [@Aisaac08](https://discuss.elastic.co/u/Aisaac08)\
**Post date:** [December 29, 2015, 8:44pm UTC](https://discuss.elastic.co/t/what-does-elasticsearch-do-when-multiple-indices-share-the-same-alias/38126/1 "2015-12-29T20:44:31Z")

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I mean exactly what I asked, I was wondering how elasticsearch will manage multiple indices with the same alias, will this be a way of load balancing or will elasticsearch pick one index randomly?  
Thanks to all of you.

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**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:** [December 29, 2015, 8:59pm UTC](https://discuss.elastic.co/t/what-does-elasticsearch-do-when-multiple-indices-share-the-same-alias/38126/2 "2015-12-29T20:59:01Z")

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It'll query both when you query and it'll refuse to write to the index if you try write to it.

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**Author:** ![Aisaac08](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/aisaac08/32/6903_2.png) [@Aisaac08](https://discuss.elastic.co/u/Aisaac08)\
**Post date:** [December 30, 2015, 2:56am UTC](https://discuss.elastic.co/t/what-does-elasticsearch-do-when-multiple-indices-share-the-same-alias/38126/3 "2015-12-30T02:56:16Z")

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Isn't that to expensive if ES have to query both indices at the same time? Why would I query two indices with the same structure instead of querying just one? Could you clarify my doubts please?

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 5, 2017, 11:27pm UTC](https://discuss.elastic.co/t/what-does-elasticsearch-do-when-multiple-indices-share-the-same-alias/38126/4 "2017-07-05T23:27:57Z")

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Closed on July 5, 2017, 11:27pm UTC