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db.collection.reIndex()

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Behavior

db.collection.reIndex()

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 reIndex command.

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

The db.collection.reIndex() drops all indexes on a collection and recreates them. This operation may be expensive for collections that have a large amount of data and/or a large number of indexes.

Warning

For most users, the db.collection.reIndex() operation is unnecessary.
Avoid running db.collection.reIndex() against a collection in a replica set.
Do not run db.collection.reIndex() against a collection in a sharded cluster.
Changed in version 4.2: MongoDB disallows db.collection.reIndex() to be run on a mongos, implementing a stronger restriction against running db.collection.reIndex() for a collection in a sharded cluster.

Behavior

Note

For replica sets, db.collection.reIndex() will not propagate from the primary to secondaries. db.collection.reIndex() will only affect a single mongod instance.

Resource Locking

Changed in version 4.2.2.

For MongoDB 4.2.2 and later, db.collection.reIndex() obtains an exclusive (W) lock on the collection and blocks other operations on the collection until it completes.

For more information on locking in MongoDB, see FAQ: Concurrency.