Details
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Bug
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Status: Closed
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Minor - P4
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Resolution: Duplicate
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None
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None
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None
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ALL
Description
In following example, collection has 3 matching docs on condition, and is using index to match.
If adding a skip(2), it only returns 1 document.
You would expect nscanned=3 but nscannedObjects should be 1, not 3, since 2 docs are skipped.
Is that just counting bug or are we actually looking at docs, which would make skip very inefficient?
foo:PRIMARY> db.testindex.find({a:5}).skip(2).explain()
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{
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"cursor" : "BtreeCursor a_1",
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"nscanned" : 3,
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"nscannedObjects" : 3,
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"n" : 1,
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"millis" : 0,
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"nYields" : 0,
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"nChunkSkips" : 0,
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"isMultiKey" : true,
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"indexOnly" : false,
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"indexBounds" : {
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"a" : [
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[
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5,
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5
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]
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]
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}
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}
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Attachments
Issue Links
- duplicates
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SERVER-13946 Consider putting skip stages below fetch stages
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- Closed
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- related to
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SERVER-10448 Revamp explain() formatting
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- Closed
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