db.xxx.ensureIndex({x:1},{partialFilterExpression:{bin:true}})
> db.xxx.find({bin:true,x:1}).explain() { "queryPlanner" : { "plannerVersion" : 1, "namespace" : "test.xxx", "indexFilterSet" : false, "parsedQuery" : { "$and" : [ {"bin" : {"$eq" : true}}, {"x" : {"$eq" : 1}} ] }, "winningPlan" : { "stage" : "FETCH", "filter" : {"bin" : {"$eq" : true}}, "inputStage" : { "stage" : "IXSCAN", "keyPattern" : {"x" : 1}, "indexName" : "x_1", "isMultiKey" : false, "multiKeyPaths" : { "x" : [ ] }, "isUnique" : false, "isSparse" : false, "isPartial" : true, "indexVersion" : 2, "direction" : "forward", "indexBounds" : { "x" : [ "[1.0, 1.0]" ] } } }, "rejectedPlans" : [ ] }, "serverInfo" : { "host" : "AD-MAC10G.local", "port" : 27017, "version" : "3.4.2", "gitVersion" : "3f76e40c105fc223b3e5aac3e20dcd026b83b38b" }, "ok" : 1 }
There's no need to do the FETCH with a check on bin:true since that condition is already satisfied by the index partial filterexpression
- is duplicated by
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SERVER-29247 COUNT_SCAN not used for partial indexes
- Closed
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SERVER-42647 Compound partialFilterExpression not being used - despite correct index chosen
- Closed
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SERVER-44836 count_documents with filter does not use the partialFilterExpression index right when the keys in the filter are indexed
- Closed
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SERVER-48777 Covered Queries do not work with partial indices
- Closed
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SERVER-32035 Index doesn't cover a query for a partial filter expression index under certain circumstances
- Closed
- is related to
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SERVER-26896 Use knowledge about partial index filter expression to determine whether $exists predicate can be covered
- Backlog
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SERVER-75025 [CQF] Add test for optimizer-specific fix for SERVER-28889
- Backlog
- related to
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SERVER-29247 COUNT_SCAN not used for partial indexes
- Closed
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SERVER-55065 Null queries should be covered by index where possible with current index format
- Closed
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SERVER-56020 Unnecessary FETCH stage
- Closed
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SERVER-26580 allow using partial index on query where predicate matches only partial filter expression
- Backlog