Да, $or заявка ще използва индекси, както е подходящо. Например:
> db.test.ensureIndex({a:1})
> db.test.ensureIndex({b:1})
> db.test.find({$or:[{a:1}, {b:2}]}).explain()
{
"clauses" : [
{
"cursor" : "BtreeCursor a_1",
"nscanned" : 0,
"nscannedObjects" : 0,
"n" : 0,
"millis" : 0,
"nYields" : 0,
"nChunkSkips" : 0,
"isMultiKey" : false,
"indexOnly" : false,
"indexBounds" : {
"a" : [
[
1,
1
]
]
}
},
{
"cursor" : "BtreeCursor b_1",
"nscanned" : 0,
"nscannedObjects" : 0,
"n" : 0,
"millis" : 1,
"nYields" : 0,
"nChunkSkips" : 0,
"isMultiKey" : false,
"indexOnly" : false,
"indexBounds" : {
"b" : [
[
2,
2
]
]
}
}
],
"nscanned" : 0,
"nscannedObjects" : 0,
"n" : 0,
"millis" : 1
}