Searching for ranges in mongo - mongodb

Question

What's the most efficient way to find data in Mongo, when the input data is a single value, and the collection data contains min/max ranges? E.g:
record = { min: number, max: number, payload }
Need to locate a record for a number that falls within the min/max range of the record. The ranges never intersect. There is no predictability about the size of the ranges.
The collection has ~6M records in it. If I unpack the ranges (have records for each value in range), I would be looking at about 4B records instead.
I've created the compound index of {min:1,max:1}, but attempt to search using:
db.block.find({min:{$lte:value},max:{$gte:value})
... takes anywhere from few to tens of seconds. Below are the output of explain() and getIndexes(). Is there any trick I can apply to make the search execute significantly faster?
NJmongo:PRIMARY> db.block.getIndexes()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "mispot.block",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"min" : 1,
"max" : 1
},
"ns" : "mispot.block",
"name" : "min_1_max_1"
}
]
NJmongo:PRIMARY> db.block.find({max:{$gte:1135194602},min:{$lte:1135194602}}).explain()
{
"cursor" : "BtreeCursor min_1_max_1",
"isMultiKey" : false,
"n" : 1,
"nscannedObjects" : 1,
"nscanned" : 1199049,
"nscannedObjectsAllPlans" : 1199050,
"nscannedAllPlans" : 2398098,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 7534,
"nChunkSkips" : 0,
"millis" : 5060,
"indexBounds" : {
"min" : [
[
-1.7976931348623157e+308,
1135194602
]
],
"max" : [
[
1135194602,
1.7976931348623157e+308
]
]
},
"server" : "ccc:27017"
}

Answer 1

If the ranges of your block records never overlap, then you can accomplish this much faster with:
db.block.find({min:{$lte:value}}).sort({min:-1}).limit(1)
This query will return almost instantly since it can find the record with a simple lookup in the index.
The query you are running is slow because the two clauses each match on millions of records that must be merged. In fact, I think your query would run faster (maybe much faster) with separate indexes on min and max since the max part of your compound index can only be used for a given min -- not to search for documents with a specific max.