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Type:
Improvement
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Resolution: Done
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Priority:
Major - P3
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None
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Affects Version/s: 1.6.3
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Component/s: Index Maintenance, Querying
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Labels:
-
Environment:Windows, Unix
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Query
I have a collection called PartOffer with a multikey called 'p'. Typical PartOffer looks like:
{title:"My offer", p:{carFuel:9023, engine:232}}
I created an index on p:
db.PartOffer.ensureIndex({p:1})
But when using dot notation to find all offers depending on a property inside p, then the index is not used:
> db.PartOffer.find({"p.carFuel":9086}).explain()
{
"cursor" : "BasicCursor",
"nscanned" : 65424,
"nscannedObjects" : 65424,
"n" : 1139,
"millis" : 126,
"indexBounds" : {
}
}
But when not using dot notation, the index is used:
> db.PartOffer.find({p:{carFuel:9086}}).explain()
{
"cursor" : "BtreeCursor p_1",
"nscanned" : 21,
"nscannedObjects" : 21,
"n" : 21,
"millis" : 0,
"indexBounds" : {
"p" : [
[
{
"carFuel" : 9086
},
{
"carFuel" : 9086
}
]
]
}
}