Spring/spring-data-mongodb
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Allow to estimate document count.

Browse Source 
This commit introduce an option that allows users to opt in on using estimatedDocumentCount instead of countDocuments in case the used filter query is empty.
To still be able to retrieve the exact number of matching documents we also introduced MongoTemplate#exactCount.

Closes: #3522
Original pull request: #3951.
This commit is contained in:
Christoph Strobl
2022-01-27 12:30:34 +01:00
committed by Mark Paluch
parent dab5473740
commit d16013aa6b
9 changed files with 410 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
src/main/asciidoc/reference/mongodb.adoc
View File

@@ -2158,6 +2158,12 @@ So in version 2.x `MongoOperations.count()` would use the collection statistics
As of Spring Data MongoDB 3.x any `count` operation uses regardless the existence of filter criteria the aggregation-based count approach via MongoDBs `countDocuments`.
If the application is fine with the limitations of working upon collection statistics `MongoOperations.estimatedCount()` offers an alternative.
[TIP]
====
By setting `MongoTemplate#useEstimatedCount(...)` to `true` _MongoTemplate#count(...)_ operations, that use an empty filter query, will be delegated to `estimatedCount`, as long as there is no transaction active and the template is not bound to a <<mongo.sessions,session>>.
It will still be possible to obtain exact numbers via `MongoTemplate#exactCount`, but may speed up things.
====
[NOTE]
====
MongoDBs native `countDocuments` method and the `$match` aggregation, do not support `$near` and `$nearSphere` but require `$geoWithin` along with `$center` or `$centerSphere` which does not support `$minDistance` (see https://jira.mongodb.org/browse/SERVER-37043).