MongoDB是否跟踪每个索引在查询中使用多少次？
> db.demo508.createIndex({"FirstName":1});
{
"createdCollectionAutomatically" : true,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}让我们创建一个包含文档的集合-
> db.demo508.insertOne({"FirstName":"John"});{
"acknowledged" : true,
"insertedId" : ObjectId("5e883818987b6e0e9d18f578")
}
> db.demo508.insertOne({"FirstName":"Chris"});{
"acknowledged" : true,
"insertedId" : ObjectId("5e88381b987b6e0e9d18f579")
}
> db.demo508.insertOne({"FirstName":"David"});{
"acknowledged" : true,
"insertedId" : ObjectId("5e88381f987b6e0e9d18f57a")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo508.find();
这将产生以下输出-
{ "_id" : ObjectId("5e883818987b6e0e9d18f578"), "FirstName" : "John" }
{ "_id" : ObjectId("5e88381b987b6e0e9d18f579"), "FirstName" : "Chris" }
{ "_id" : ObjectId("5e88381f987b6e0e9d18f57a"), "FirstName" : "David" }以下是查询以跟踪每个索引在查询中使用了多少次-
> db.demo508.aggregate([{ $indexStats: { } }]).pretty();这将产生以下输出-
{
"name" : "_id_",
"key" : {
"_id" : 1
},
"host" : "DESKTOP-QN2RB3H:27017",
"accesses" : {
"ops" : NumberLong(0),
"since" : ISODate("2020-04-04T07:32:27.394Z")
}
}
{
"name" : "FirstName_1",
"key" : {
"FirstName" : 1
},
"host" : "DESKTOP-QN2RB3H:27017",
"accesses" : {
"ops" : NumberLong(0),
"since" : ISODate("2020-04-04T07:32:27.527Z")
}
}