如題這是我用explain顯示出來的數據>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}