db.collection.reIndex()

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Definition

Behavior

Definition

db.collection.reIndex()

Important

mongosh Method

This is a mongosh method. This is not the documentation for Node.js or other programming language specific driver methods.

In most cases, mongosh methods work the same way as the legacy mongo shell methods. However, some legacy methods are unavailable in mongosh.

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

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

db.collection.reIndex() may only be run on standalone instances.
For most users, the db.collection.reIndex() command is unnecessary.

Behavior

For MongoDB 5.0 or later, db.collection.reIndex() may only be run on standalone instances.

For MongoDB 2.6 through MongoDB versions with featureCompatibilityVersion (fCV) set to "4.0" or earlier, MongoDB will not create an index on a collection if the index entry for an existing document exceeds the Maximum Index Key Length.

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 MongoDB 4.0.0 through 4.2.1, db.collection.reIndex() obtains a global exclusive (W) lock and blocks other operations on the mongod until it completes.

For MongoDB 3.6 and earlier, these operations db.collection.reIndex() obtains an exclusive (W) lock on the database and blocks other operations on the database until finished.

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