데이터 추가

> for (let i = 0; i < 20000; i++) {
... db.test.save({ num: i });
... }

explain()

• 결과보기

explain("executionStats")

• 결과보기

createIndex

> db.test.createIndex({ num: 1 })
{
        "createdCollectionAutomatically" : false,
        "numIndexesBefore" : 1,
        "numIndexesAfter" : 2,
        "ok" : 1
}

getIndexs()

> db.test.getIndexes()
[
        {
                "v" : 2,
                "key" : {
                        "_id" : 1
                },
                "name" : "_id_",
                "ns" : "test.test"
        },
        {
                "v" : 2,
                "key" : {
                        "num" : 1
                },
                "name" : "num_1",
                "ns" : "test.test"
        }
]

그 이후 실행계획

> db.test.find({ num: 500 }).explain("executionStats")
{
        "queryPlanner" : {
                "plannerVersion" : 1,
                "namespace" : "test.test",
                "indexFilterSet" : false,
                "parsedQuery" : {
                        "num" : {
                                "$eq" : 500
                        }
                },
                "winningPlan" : {
                        "stage" : "FETCH",
                        "inputStage" : {
                                "stage" : "IXSCAN",
                                "keyPattern" : {
                                        "num" : 1
                                },
                                "indexName" : "num_1",
                                "isMultiKey" : false,
                                "multiKeyPaths" : {
                                        "num" : [ ]
                                },
                                "isUnique" : false,
                                "isSparse" : false,
                                "isPartial" : false,
                                "indexVersion" : 2,
                                "direction" : "forward",
                                "indexBounds" : {
                                        "num" : [
                                                "[500.0, 500.0]"
                                        ]
                                }
                        }
                },
                "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,
                        "needYield" : 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,
                                "needYield" : 0,
                                "saveState" : 0,
                                "restoreState" : 0,
                                "isEOF" : 1,
                                "invalidates" : 0,
                                "keyPattern" : {
                                        "num" : 1
                                },
                                "indexName" : "num_1",
                                "isMultiKey" : false,
                                "multiKeyPaths" : {
                                        "num" : [ ]
                                },
                                "isUnique" : false,
                                "isSparse" : false,
                                "isPartial" : false,
                                "indexVersion" : 2,
                                "direction" : "forward",
                                "indexBounds" : {
                                        "num" : [
                                                "[500.0, 500.0]"
                                        ]
                                },
                                "keysExamined" : 1,
                                "seeks" : 1,
                                "dupsTested" : 0,
                                "dupsDropped" : 0,
                                "seenInvalidated" : 0
                        }
                }
        },
        "serverInfo" : {
                "host" : "test-jongpak.ncl",
                "port" : 27017,
                "version" : "4.0.6",
                "gitVersion" : "caa42a1f75a56c7643d0b68d3880444375ec42e3"
        },
        "ok" : 1
}