MongoDB Learning Notes (iii)

Chapter III index operations and performance testing

The importance of indexes under big data is not much to say.

The following test used a MongoDB client tool Robomongo, you can choose to download on the Internet. Official website: http://www.robomongo.org/

Inserting test data

Insert 1 million test data first

for (Var i=1;i<1000000;i++) {var person={name: "Jack" +i,age:i,address:["Henan", "Wuhan"],course:[{name: "Shuxue", Score:i},{name: "Wuli", score:i}]}db. DemoTest.Person.insert (Person)}

Performance analysis functions (explain)

MongoDB gives us a keyword called "explain" for performance analysis.

Perform the query analysis as follows:

Db. DemoTest.Person.find ({Name: "jack5784124"}). Explain ()

从我们可以看出在没有建立索引的情况下，查询的时间大约是是615毫秒。

Create an index

Db. TestCollection.Person.ensureIndex ({name:1})

-----1 indicates the index in ascending alphabetical order

Inquire

As we can see from the graph, the query time becomes about 2 milliseconds and the performance is increased by hundreds of times times.

Unique index

As with SQL Server, you can create a unique index, and duplicate key values cannot be inserted naturally, and the use in MongoDB is as follows:

Db. TestCollection.Person.ensureIndex ({name:1},{"unique": true})

Combined index

Sometimes our query is not single-condition, may be multi-conditional, then we can set up a composite index to speed up the query.

Db. TestCollection.Person.ensureIndex ({name:1,age:1})

Delete Index

Db. TestCollection.Person.dropIndex ("index name")

MongoDB Learning Notes (iii)