Execution plan of aggregate query in MongoTempate with Spring data mongodb - mongodb

Question

I am using spring data mongodb, in that want aggregation query to implement that I am using MongoTemplate with aggregation method. When I trace the log it shows the query as follows:
find: track.$cmd { "aggregate" : "stayRecord" , "pipeline" : [ { "$match" : { "vehicleId" : { "$all" : [ 10]}}} , { "$match" : { "stayTime" : { "$gte" : { "$date" : "2016-06-20T18:30:00.000Z"}}}} , { "$match" : { "stayTime" : { "$lt" : { "$date" : "2016-06-21T18:30:00.000Z"}}}} , { "$group" : { "_id" : "$stayTime" , "count" : { "$sum" : 1}}}}
I want to know execution plan for this query.
How can I find out if my indexes are used during that query?

Answer 1

Please note that in order to follow the below steps, you need the working aggregate query which mongo shell can understand.
Follow the below steps:-
1) Go to mongo shell
2) Execute the use command to switch to your database
use <database name>
3) Execute the below query. I hope the aggregate query mentioned in the thread is syntactically correct. Also, please change the collection name accordingly in the below syntax.
db.yourCollectionName.explain().aggregate({ "stayRecord" , "pipeline" : [ { "$match" : { "vehicleId" : { "$all" : [ 10]}}} , { "$match" : { "stayTime" : { "$gte" : { "$date" : "2016-06-20T18:30:00.000Z"}}}} , { "$match" : { "stayTime" : { "$lt" : { "$date" : "2016-06-21T18:30:00.000Z"}}}} , { "$group" : { "_id" : "$stayTime" , "count" : { "$sum" : 1}}}});
2) In the output, please find the "winningPlan" element. In the input stage ("inputStage") attribute, if the query used index it will show you the value as "IXSCAN" and the index name if the query used index. Otherwise, it would show "COLLSCAN" which means the query used the collection scan (i.e. index is not used).
"winningPlan" : {
"stage" : "LIMIT",
"limitAmount" : 0,
"inputStage" : {
"stage" : "SKIP",
"skipAmount" : 0,
"inputStage" : {
"stage" : "FETCH",
"filter" : {
"user.followers_count" : {
"$gt" : 1000
}
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"created_at" : -1
},
"indexName" : "created_at_-1",
"isMultiKey" : false,
"direction" : "backward",
"indexBounds" : {
"created_at" : [
"[MinKey, MaxKey]"
]
}
}
}
}
}