# Does the dfs search type work across indexes?

**URL:** <https://discuss.elastic.co/t/does-the-dfs-search-type-work-across-indexes/14949>\
**Category:** Elasticsearch\
**Created:** [December 19, 2013, 10:36am UTC](https://discuss.elastic.co/t/does-the-dfs-search-type-work-across-indexes/14949 "2013-12-19T10:36:45Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Tim\_S](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tim_s/32/958_2.png) [@Tim\_S](https://discuss.elastic.co/u/Tim_S)\
**Post date:** [December 19, 2013, 10:36am UTC](https://discuss.elastic.co/t/does-the-dfs-search-type-work-across-indexes/14949/1 "2013-12-19T10:36:45Z")

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If I use the search type "dfs\_query\_then\_fetch", as I understand it the  
first step of the search is to go to each of the shards collecting the  
inverse document frequencies.

If I was searching across multiple indexes, would it collect the idfs from  
each of the indexes and combine them?

E.g. if I randomly split an index in half (e.g. "unsecured" and "secured"),  
if I did a search across both of those indexes, would the results (and  
their scores) be roughly similar to if I had all the documents in one index  
and just did the search on that?

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<div class="post-metadata">

**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, 2:00am UTC](https://discuss.elastic.co/t/does-the-dfs-search-type-work-across-indexes/14949/2 "2017-07-06T02:00:16Z")

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