MongoDB query not using intersection indexes - mongodb

Question

I have MongoDB 3.28 with a collection and few indexes on different fields. I'm executing a query with many filters expecting the intersection indexes to kick in, but for some reason it is not. Additionally it is not showing up in the explain(true) allPlans
The query
{
"$and": [
{
"category": {
"$in": [
1,
5
]
}
},
{
"city": {
"$in": [
"y"
]
}
},
{
"neighbourhood": {
"$in": [
"x",
null
]
}
},
{
"$or": [
{
"price": {
"$lte": 3
}
},
{
"price": null
}
]
}
]
}
db.items.find(query).explain(true)
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "xxx.items",
"indexFilterSet" : false,
"parsedQuery" : {
"$and" : [
{
"$or" : [
{
"price" : {
"$eq" : null
}
},
{
"price" : {
"$lte" : 3
}
}
]
},
{
"category" : {
"$in" : [
1,
5
]
}
},
{
"city" : {
"$in" : [
"y"
]
}
},
{
"neighbourhood" : {
"$in" : [
null,
"x"
]
}
}
]
},
"winningPlan" : {
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"$or" : [
{
"price" : {
"$eq" : null
}
},
{
"price" : {
"$lte" : 3
}
}
]
},
{
"category" : {
"$in" : [
1,
5
]
}
},
{
"neighbourhood" : {
"$in" : [
null,
"x"
]
}
}
]
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"city" : 1,
"updatedAt" : 1
},
"indexName" : "city_updatedAt",
"isMultiKey" : false,
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 1,
"direction" : "forward",
"indexBounds" : {
"city" : [
"[\"y\", \"y\"]"
],
"updatedAt" : [
"[MinKey, MaxKey]"
]
}
}
},
"rejectedPlans" : [
{
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"category" : {
"$in" : [
1,
5
]
}
},
{
"city" : {
"$in" : [
"y"
]
}
},
{
"neighbourhood" : {
"$in" : [
null,
"x"
]
}
}
]
},
"inputStage" : {
"stage" : "FETCH",
"filter" : {
"$or" : [
{
"price" : {
"$eq" : null
}
},
{
"price" : {
"$lte" : 3
}
}
]
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"price" : 1
},
"indexName" : "price_1",
"isMultiKey" : false,
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 1,
"direction" : "forward",
"indexBounds" : {
"price" : [
"[null, null]",
"[-inf.0, 3.0]"
]
}
}
}
},
{
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"$or" : [
{
"price" : {
"$eq" : null
}
},
{
"price" : {
"$lte" : 3
}
}
]
},
{
"category" : {
"$in" : [
1,
5
]
}
},
{
"neighbourhood" : {
"$in" : [
null,
"x"
]
}
}
]
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"city" : 1
},
"indexName" : "city_1",
"isMultiKey" : false,
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 1,
"direction" : "forward",
"indexBounds" : {
"city" : [
"[\"y\", \"y\"]"
]
}
}
},
{
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"$or" : [
{
"price" : {
"$eq" : null
}
},
{
"price" : {
"$lte" : 3
}
}
]
},
{
"city" : {
"$in" : [
"y"
]
}
},
{
"neighbourhood" : {
"$in" : [
null,
"x"
]
}
}
]
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"category" : 1,
"updatedAt" : -1
},
"indexName" : "category",
"isMultiKey" : false,
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 1,
"direction" : "forward",
"indexBounds" : {
"category" : [
"[1.0, 1.0]",
"[5.0, 5.0]"
],
"updatedAt" : [
"[MaxKey, MinKey]"
]
}
}
}
]
},
"serverInfo" : {
"host" : "xxx",
"port" : 27017,
"version" : "3.2.8",
"gitVersion" : "ed70e33130c977bda0024c125b56d159573dbaf0"
},
"ok" : 1
}
db.items.getIndexes()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "xxx.items"
},
{
"v" : 1,
"unique" : true,
"key" : {
"RecordID" : 1
},
"name" : "RecordID",
"ns" : "xxx.items"
},
{
"v" : 1,
"key" : {
"SubCatID" : 1,
"updatedAt" : -1
},
"name" : "category",
"ns" : "xxx.items"
},
{
"v" : 1,
"key" : {
"updatedAt" : -1
},
"name" : "updatedAt_-1",
"ns" : "xxx.items",
"background" : true
},
{
"v" : 1,
"key" : {
"city" : 1
},
"name" : "city_1",
"ns" : "xxx.items"
},
{
"v" : 1,
"key" : {
"search" : 1
},
"name" : "search_1",
"ns" : "xxx.items",
"background" : true
},
{
"v" : 1,
"key" : {
"rooms" : 1
},
"name" : "rooms_1",
"ns" : "xxx.items",
"background" : true
},
{
"v" : 1,
"key" : {
"price" : 1
},
"name" : "price_1",
"background" : true,
"ns" : "xxx.items"
},
{
"v" : 1,
"key" : {
"city" : 1,
"updatedAt" : 1
},
"name" : "city_updatedAt",
"ns" : "xxx.items",
"background" : true
}
]
Sample record: db.items.find().limit(1)[0]
{
"_id" : ObjectId("568ee714578df40300ac65b0"),
"type" : "z",
"CatID" : 2,
"category" : 5,
"RecordID" : "1469882",
"title" : "x - x x",
"subtitle" : "x/x' - 7 x",
"subtitle2" : "3,700,000",
"someProps1" : false,
"someProps2" : 14,
"subtite3" : "some title",
"type" : 3,
"img" : "x",
"URL" : "y",
"someProps" : 0,
"latitude" : 31.809843,
"longitude" : 35.191562,
"Map_address" : {
"adress" : "x - x x",
"lat" : 31.809843,
"long" : 35.191562
},
"created_at" : ISODate("2016-01-07T22:30:44.425Z"),
"updated_at" : ISODate("2016-01-14T15:53:43.110Z"),
"price" : 3700000,
"rooms" : 7,
"updatedAt" : 1452292244,
"search" : "x - x x 14-01-2016",
"street" : null
}