db.collection.hideIndex()

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Definition

Syntax
Behavior
Access Control
Example

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Definition

db.collection.hideIndex()

New in version 4.4.

Important

mongo Shell Method

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

Hides an existing index from the query planner. An index hidden from the query planner is not evaluated as part of query plan selection.

By hiding an index from the planner, users can evaluate the potential impact of dropping an index without actually dropping the index. If the impact is negative, the user can unhide the index instead of having to recreate a dropped index. And because indexes are fully maintained while hidden, the indexes are immediately available for use once unhidden.

For details, see Hidden Indexes.

Syntax

db.collection.hideIndex(<index>)

Parameters

The db.collection.hideIndex() method takes the following parameter:

Parameter	Type	Description
`index`	string or document	Specifies the index to hide from the query planner. You can specify the index either by the index name or by the index specification document. Tip You can use the `db.collection.getIndexes()` method to find the index name or the index specification document. To hide a text index, specify the index name.

The db.collection.hideIndex() is a mongo shell wrapper for the collMod command.

Behavior

Feature Compatibility Version

To hide an index, you must have featureCompatibilityVersion set to 4.4 or greater. However, once hidden, the index remains hidden even with featureCompatibilityVersion set to 4.2 on MongoDB 4.4 binaries.

Restrictions

You cannot hide the _id index.

Index Modifications Reset Statistics

Hiding an unhidden index resets its $indexStats.

No-op

Hiding an already hidden index has no effect on the index. However, the operation will still generate an empty oplog entry.

Access Control

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 hides an existing index.

First, use db.collection.createIndex() to create an index without hiding:

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

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

db.restaurants.hideIndex( "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",
      "hidden" : true
   }
]

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