if inscribe
This is the data I showed with explain.
> db.users.explain("allPlansExecution").find({username:'user101'})
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "test.users",
"indexFilterSet" : false,
"parsedQuery" : {
"username" : {
"$eq" : "user101"
}
},
"winningPlan" : {
"stage" : "FETCH",
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"username" : 1
},
"indexName" : "username_1",
"isMultiKey" : false,
"direction" : "forward",
"indexBounds" : {
"username" : [
"[\"user101\", \"user101\"]"
]
}
}
},
"rejectedPlans" : [ ]
},
"executionStats" : {
"executionSuccess" : true,
"nReturned" : 1,
"executionTimeMillis" : 0,
"totalKeysExamined" : 1,
"totalDocsExamined" : 1,
"executionStages" : {
"stage" : "FETCH",
"nReturned" : 1,
"executionTimeMillisEstimate" : 0,
"works" : 2,
"advanced" : 1,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 0,
"restoreState" : 0,
"isEOF" : 1,
"invalidates" : 0,
"docsExamined" : 1,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 1,
"executionTimeMillisEstimate" : 0,
"works" : 2,
"advanced" : 1,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 0,
"restoreState" : 0,
"isEOF" : 1,
"invalidates" : 0,
"keyPattern" : {
"username" : 1
},
"indexName" : "username_1",
"isMultiKey" : false,
"direction" : "forward",
"indexBounds" : {
"username" : [
"[\"user101\", \"user101\"]"
]
},
"keysExamined" : 1,
"dupsTested" : 0,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
}
},
"allPlansExecution" : [ ]
},
"serverInfo" : {
"host" : "mongo2",
"port" : 27017,
"version" : "3.0.0",
"gitVersion" : "a841fd6394365954886924a35076691b4d149168"
},
"ok" : 1
}
I just checked the documents and blamed myself for not reading the results carefully. .
queryPlanner.winningPlan.inputStage.stage
Column Display Query Policy
–IXSCAN
Indicates that an Index query is used
–COLLSCAN
Indicates the use of column queries, that is, comparing the past one by one.
cursor
Index name in moved toqueryPlanner.winningPlan.inputStage.indexName
Used in 3.0
executionStats.totalDocsExamined
To display the total number of documents to be checked and replace them.nscanned
.