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When I search in Mongodb with same query term by findOne / find, findOne is much faster than find.

In my search case, I just need know if it is exists, So I want search engine pick one and return, and run my search query fast.

And when I search anything in ElasticSearch, I can always get total of searching results, It's not very slow but not fast as I expected.

FYI, My elasticsearch store about 2 million documents, and some search terms hint over 200 thousands documents, which may take over 500 ms.

I'm looking for a function like Mongodb's findOne, which can slow my query time to less than 100 ms.

Or is there any other solutions ?

Thanks.

vincent wen
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  • I think the solution would be to limit the search results by specifying a result set size http://www.elasticsearch.org/guide/reference/api/search/from-size.html – Dan D. Nov 20 '12 at 03:32
  • Even I set from, size in search query, elasticsearch still can get total number, So I guess it look around all index and It's not the fast solution – vincent wen Nov 20 '12 at 03:42
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    Ah, So: The problem is not then limiting the result set. But that even with that ElasticSearch still find all the possible results and returns an unwanted count which delays the request that it shouldn't have needed to find. – Dan D. Nov 20 '12 at 03:47
  • @DanD. Yes. Use mongodb findOne, 19 queries in 500 ms, but elasticsearch cost nearly 5 seconds to do same thing. I'm wondering if elasticsearch is suitable to do this work – vincent wen Nov 20 '12 at 03:58
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    I think you might test a limit filter http://www.elasticsearch.org/guide/reference/query-dsl/limit-filter.html as the answer to http://stackoverflow.com/questions/8583344/elastic-search-limit-results reports that it would provide the requested behavior. And if that is so then this question is a duplicate of that one. – Dan D. Nov 20 '12 at 04:09
  • Thank you, I guess It's the answer. Testing first – vincent wen Nov 20 '12 at 04:15

1 Answers1

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Try either count api:

http://www.elasticsearch.org/guide/reference/api/count.html

Or search_type=count:

http://www.elasticsearch.org/guide/reference/api/search/search-type.html

Either should be more efficient if you don't need any hit data, though they do still calculate total document count.

barnybug
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