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Type:
Question
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Resolution: Done
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Priority:
Major - P3
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Affects Version/s: None
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Component/s: Index Maintenance
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3
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for a collection "foo" with index
{x:1}, will a query like db.foo.find({},{_id:0,x1}).hint(
{x:1}) touch the data? or will it be completely answered via the data stored in the index?
The explain verifies that it's "indexOnly", but I'm not sure what that means wrt to the actual results:
> db.foo.find({},{_id:0,x:1}).hint({x:1}).explain()
{
"cursor" : "BtreeCursor x_1",
"isMultiKey" : false,
"n" : 100,
"nscannedObjects" : 100,
"nscanned" : 100,
"nscannedObjectsAllPlans" : 100,
"nscannedAllPlans" : 100,
"scanAndOrder" : false,
"indexOnly" : true,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 0,
"indexBounds" : {
"x" : [
[
{
"$minElement" : 1
},
{
"$maxElement" : 1
}
]
]
},
"server" : "hoffrocket.local:27017"
}