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Type:
Bug
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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: 2.4.3, 2.4.7
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Component/s: Querying
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ALL
Setting the .min() or .max() explicitly on a find and using a descending sort seems not to work.
> db.docs.drop() > for (var i=0; i<10; i++) { db.docs.insert({number: i}) } > db.docs.ensureIndex({number: 1})
no sort
> db.docs.find().max({number: 4})
{ "_id" : ObjectId("51834d678d284e5c5e3ea7e3"), "number" : 0 }
{ "_id" : ObjectId("51834d678d284e5c5e3ea7e4"), "number" : 1 }
{ "_id" : ObjectId("51834d678d284e5c5e3ea7e5"), "number" : 2 }
{ "_id" : ObjectId("51834d678d284e5c5e3ea7e6"), "number" : 3 }
ascending sort
> db.docs.find().max({number: 4}).sort({number: 1})
{ "_id" : ObjectId("51834d678d284e5c5e3ea7e3"), "number" : 0 }
{ "_id" : ObjectId("51834d678d284e5c5e3ea7e4"), "number" : 1 }
{ "_id" : ObjectId("51834d678d284e5c5e3ea7e5"), "number" : 2 }
{ "_id" : ObjectId("51834d678d284e5c5e3ea7e6"), "number" : 3 }
descending sort
> db.docs.find().max({number: 4}).sort({number: -1})
>
I would expect to get the 4 documents back in the 'reverse order' case, in number order: 3, 2, 1, 0. Instead, I get 0 documents back.
explain of ascending sort
> db.docs.find().max({number: 4}).sort({number: 1}).explain()
{
"cursor" : "BtreeCursor number_1",
"isMultiKey" : false,
"n" : 4,
"nscannedObjects" : 4,
"nscanned" : 4,
"nscannedObjectsAllPlans" : 4,
"nscannedAllPlans" : 4,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 0,
"indexBounds" : {
"start" : {
"number" : {
"$minElement" : 1
}
},
"end" : {
"number" : 4
}
},
"server" : "capslock.local:27017"
}
explain of descending sort
> db.docs.find().max({number: 4}).sort({number: -1}).explain()
{
"cursor" : "BtreeCursor number_1 reverse",
"isMultiKey" : false,
"n" : 0,
"nscannedObjects" : 0,
"nscanned" : 0,
"nscannedObjectsAllPlans" : 0,
"nscannedAllPlans" : 0,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 0,
"indexBounds" : {
"start" : {
"number" : {
"$minElement" : 1
}
},
"end" : {
"number" : 4
}
},
"server" : "capslock.local:27017"
}
- depends on
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- Closed
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SERVER-10026 New query system
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- Closed
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- duplicates
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- Closed
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- is duplicated by
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SERVER-9540 How to get the previous mongoDB document from a compound index
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- Closed
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- is related to
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SERVER-17076 Consider removing IndexBounds::isSimpleRange
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- Closed
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- related to
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- Closed
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