Best way to query for document existence

[Peter]

Hi there,

we currently do these kind of queries by checking whether:
count(query) > 0

however, this might not be the best solution for huge collections, as
count does not stop traversing the collection after the first match,
as would be feasible for this use case.

So I was wondering whether checking upon a find(query).limit(1) might
be a better solution?

Also, how about a seperate exists(query) command?

[Max Schireson]

That should be better for exactly the reason you state. Be sure to drop any sorts which are part of your query.

Submit the request for exists on JIRA. Seems useful to me. In some cases it could be slightly faster by not returning results (eg if the document that matched first was big - which is the one downside I see to your approach but it strikes me as overall better than a count).

-- Max

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[Peter]

https://jira.mongodb.org/browse/SERVER-6033