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Type: Improvement
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Resolution: Duplicate
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Priority: Major - P3
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None
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Affects Version/s: None
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Component/s: Querying
Covered indexes work with straight cursor reads, but not in memory sorts. However, explain output incorrectly states that the queries are 'indexOnly'.
> c.find( {}, {_id:0,b:1} ).hint( {a:1,b:1} ).sort( {b:1} ).explain() { "cursor" : "BtreeCursor a_1_b_1", "nscanned" : 0, "nscannedObjects" : 0, "n" : 0, "scanAndOrder" : true, "millis" : 1, "nYields" : 0, "nChunkSkips" : 0, "isMultiKey" : false, "indexOnly" : true, "indexBounds" : { "a" : [ [ { "$minElement" : 1 }, { "$maxElement" : 1 } ] ], "b" : [ [ { "$minElement" : 1 }, { "$maxElement" : 1 } ] ] }, "server" : "Aaron-Staples-MacBook-Pro.local:27017" }
- is duplicated by
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SERVER-15221 Planner sort analysis should not add FETCH stage if sort key included in index key pattern
- Closed
- is related to
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SERVER-4161 nscannedObjects is not calculated properly for covered index queries
- Closed
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SERVER-5759 indexOnly in explain() is not reported correctly
- Closed