db.collection.unhideIndex()

Definition

db.collection.unhideIndex()

Important

mongosh Method

This page documents a mongosh method. This is not the documentation for database commands or language-specific drivers, such as Node.js.

For the database command, see the index.hidden collection option set using the collMod command.

For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.

For the legacy mongo shell documentation, refer to the documentation for the corresponding MongoDB Server release:

mongo shell v4.4

Unhides an existing index from the query planner. Once unhidden, the indexes are immediately available for use.

Syntax

db.collection.unhideIndex(<index>)

Behavior

Required Access

If the deployment enforces authentication/authorization, you must have the collMod privilege in the collection's database.

The built-in role dbAdmin provides the required privileges.

Example

The following example unhides an existing index.

First, use db.collection.createIndex() to create a hidden index:

db.restaurants.createIndex( { borough: 1, ratings: 1 }, { hidden: true } );

To verify, run db.collection.getIndexes() on the restaurants collection:

db.restaurants.getIndexes();

The operation returns the following information:

[
   {
      "v" : 2,
      "key" : {
         "_id" : 1
      },
      "name" : "_id_"
   },
   {
      "v" : 2,
      "key" : {
         "borough" : 1,
         "ratings" : 1
      },
      "name" : "borough_1_ratings_1",
      "hidden" : true
   }
]

The index option hidden is only returned if the value is true.

To unhide the index, you can specify either the index key specification document or the index name to the db.collection.unhideIndex() method. The following specifies the index name:

db.restaurants.unhideIndex( "borough_1_ratings_1" );

To verify, run db.collection.getIndexes() on the restaurants collection:

db.restaurants.getIndexes()

The operation returns the following information:

[
   {
      "v" : 2,
      "key" : {
         "_id" : 1
      },
      "name" : "_id_"
   },
   {
      "v" : 2,
      "key" : {
         "borough" : 1,
         "ratings" : 1
      },
      "name" : "borough_1_ratings_1"
   }
]

The index option hidden no longer appears as part of the borough_1_ratings_1 index since the field is only returned if the value is true.