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Type:
Task
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Resolution: Done
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Priority:
Minor - P4
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Affects Version/s: None
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Component/s: Server
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Labels:None
The documentation for getlasterror.n is not entirely accurate. It states:
n reports the number of documents updated or removed, if the preceding operation was an update or remove operation.
It should say something like:
n reports the number of documents matched by the query to an update or a remove, if the preceding operation was an update or remove operation. For a remove, the number matched will equal the number removed. But for an update, the number matched may be smaller than the number actually modified.
For example:
> db.foo.insert({x:1, y:2})
WriteResult({ "nInserted" : 1 })
> db.foo.update({x:1}, {$set: {y:2}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 0 })
> db.runCommand( { getLastError: 1, w: 1 } )
{
"connectionId" : 22,
"updatedExisting" : true,
"n" : 1,
"syncMillis" : 0,
"writtenTo" : null,
"err" : null,
"ok" : 1
}
and for an upsert:
> db.foo.update({x:3}, {$set:{y:3}}, {upsert:true})
WriteResult({
"nMatched" : 0,
"nUpserted" : 1,
"nModified" : 0,
"_id" : ObjectId("555f835e3bd3ad1bd7a14b9f")
})
> db.runCommand( { getLastError: 1, w: 1 } )
{
"connectionId" : 22,
"n" : 0,
"syncMillis" : 0,
"writtenTo" : null,
"err" : null,
"ok" : 1
}
- is related to
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SERVER-17999 Regression between MongoDB 2.4 and 2.6
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- Closed
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SERVER-18639 Expose number of modified documents in getLastError output
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- Closed
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- related to
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- Closed
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