mongodb中的索引创建

作者: 幼姿沫 | 来源:发表于2020-10-28 08:14 被阅读0次

一索引的建立

索引的建立：是为了提升查询的速度

测试插入100000条数据到数据库中

for(i=0;i<100000;i++){

db.test.insert({name:'test'+i,age:i})

}

查询第1000名人员的信息并且进行显示

db.test.find({name:'test1000'})

{ "_id" : ObjectId("5f9561df1221b7ffcd13e3ca"), "name" : "test1000", "age" : 1000 }

查询程序执行的时间

db.test.find({name:'test100000'}).explain('executionStats')

{

"queryPlanner" : {

"plannerVersion" : 1,

"namespace" : "mydb.test",

"indexFilterSet" : false,

"parsedQuery" : {

"name" : {

"$eq" : "test1000"

}

},

"winningPlan" : {

"stage" : "FETCH",

"inputStage" : {

"stage" : "IXSCAN",

"keyPattern" : {

"name" : 1

},

"indexName" : "name_1",

"isMultiKey" : false,

"multiKeyPaths" : {

"name" : [ ]

},

"isUnique" : false,

"isSparse" : false,

"isPartial" : false,

"indexVersion" : 2,

"direction" : "forward",

"indexBounds" : {

"name" : [

"[\"test1000\", \"test1000\"]"

]

}

}

},

"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" : {

"name" : 1

},

"indexName" : "name_1",

"isMultiKey" : false,

"multiKeyPaths" : {

"name" : [ ]

},

"isUnique" : false,

"isSparse" : false,

"isPartial" : false,

"indexVersion" : 2,

"direction" : "forward",

"indexBounds" : {

"name" : [

"[\"test1000\", \"test1000\"]"

]

},

"keysExamined" : 1,

"seeks" : 1,

"dupsTested" : 0,

"dupsDropped" : 0,

"seenInvalidated" : 0

}

}

},

"serverInfo" : {

"host" : "LAPTOP-TFVLBBKE",

"port" : 27017,

"version" : "3.4.6",

"gitVersion" : "c55eb86ef46ee7aede3b1e2a5d184a7df4bfb5b5"

},

"ok" : 1

}