如何检查我的汇总查询是好还是坏？我已经使用了“解释”，但这并不具体。
这是我的汇总“解释”的输出。
{
"waitedMS" : NumberLong(0),
"stages" : [
{
"$cursor" : {
"query" : {
"keys.license_id" : ObjectId("580eeb7fb79bec95648775a2"),
"deleted.status" : {
"$ne" : 1
}
},
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "serpentsmsapp.conversations",
"indexFilterSet" : false,
"parsedQuery" : {
"$and" : [
{
"keys.license_id" : {
"$eq" : ObjectId("580eeb7fb79bec95648775a2")
}
},
{
"$not" : {
"deleted.status" : {
"$eq" : 1
}
}
}
]
},
"winningPlan" : {
"stage" : "COLLSCAN",
"filter" : {
"$and" : [
{
"keys.license_id" : {
"$eq" : ObjectId("580eeb7fb79bec95648775a2")
}
},
{
"$not" : {
"deleted.status" : {
"$eq" : 1
}
}
}
]
},
"direction" : "forward"
},
"rejectedPlans" : [ ]
}
}
},
{
"$sort" : {
"sortKey" : {
"_id" : 1,
"keys.license_id" : 1,
"status.deleted" : 1
}
}
},
{
"$lookup" : {
"from" : "conversation_messages",
"as" : "cmf",
"localField" : "_id",
"foreignField" : "keys.conv_id",
"unwinding" : {
"preserveNullAndEmptyArrays" : false
}
}
},
{
"$match" : {
"cmf.deleted.status" : 0
}
},
{
"$sort" : {
"sortKey" : {
"cmf.deleted.status" : -1
}
}
},
{
"$group" : {
"_id" : {
"id" : "$_id",
"number" : "$number",
"mode" : "$mode",
"keys" : "$keys",
"ports" : "$ports",
"user_assign" : "$user_assign",
"spam" : "$spam"
},
"cm_field" : {
"$last" : {
"id" : "$cmf._id",
"message" : "$cmf.message",
"ports" : "$cmf.ports",
"mode" : "$cmf.mode",
"keys" : "$cmf.keys",
"status" : "$cmf.status",
"date" : "$cmf.updated"
}
},
"counts" : {
"$sum" : "$cmf.status"
},
"sms_mode" : {
"$addToSet" : "$cmf.mode"
}
}
},
{
"$sort" : {
"sortKey" : {
"cm_field.date" : -1
},
"limit" : NumberLong(5000)
}
},
{
"$group" : {
"_id" : "$_id",
"cm_field" : {
"$last" : "$cm_field"
},
"counts" : {
"$first" : "$counts"
},
"sms_mode" : {
"$first" : "$sms_mode"
}
}
}
],
"ok" : 1
}
在执行查询之前，如何查看扫描的文档数量？