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reIndex¶
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reIndex
¶ Tip
In the mongo Shell, this command can also be run through the
db.collection.reIndex
helper method.Helper methods are convenient for mongo users, but they may not return the same level of information as database commands. In cases where the convenience is not needed or the additional return fields are required, use the database command.
The
reIndex
command 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
Use the following syntax:
The command takes the following fields:
Field Description reIndex The name of the collection to reindex.
Behavior¶
Note
For replica sets, reIndex
will not propagate from the
primary to secondaries. reIndex
will
only affect a single mongod
instance.
Resource Locking¶
Changed in version 4.2.2.
For MongoDB 4.2.2 and later, 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, reIndex
obtains a global
exclusive (W) lock and blocks other operations on the
mongod
until it completes.
For MongoDB 3.6 and earlier, 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.
See
Index Builds on Populated Collections for more information on the behavior of indexing operations in MongoDB.