Managing existing indexes

In this recipe, we will be looking at some common operations we can perform on indexes like viewing, deleting, checking index sizes, and re-indexing.

Getting ready

For this recipe, load the sample dataset and create an index on the city field, as described in the previous recipe.

How to do it...

1. We begin by connecting to the mongo shell of the server and viewing all indexes on the system:

> db.mockdata.getIndexes()

The following result is obtained:

[
  {
    "v" : 2,
    "key" : {
      "_id" : 1
    },
    "name" : "_id_",
    "ns" : "mydb.mockdata"
  },
  {
    "v" : 2,
    "key" : {
      "city" : 1,
      "first_name" : 1
    },
    "name" : "city_1_first_name_1",
    "ns" : "mydb.mockdata"
  }
]

2. Execute a dropIndex() command to delete a particular index:

> db.mockdata.dropIndex('city_1_first_name_1')

You should see the following result:

 

{ "nIndexesWas" : 2, "ok" : 1 }

3. Let's recreate the index:

> db.mockdata.createIndex({'city':1}, {name: 'city_index'})

{
   ...