renameCollection

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Definition定义

renameCollection

Changes the name of an existing collection. Specify collection names to renameCollection in the form of a complete namespace (<database>.<collection>).

Issue the renameCollection command against the admin database.

The command takes the following form:

{ renameCollection: "<source_namespace>",
  to: "<target_namespace>",
  dropTarget: <true|false>,
  writeConcern: <document>,
  comment: <any> }

The command contains the following fields:

Field字段Type类型Description描述
renameCollection string The namespace of the collection to rename. The namespace is a combination of the database name and the name of the collection.
to string The new namespace of the collection. If the new namespace specifies a different database, the renameCollection command copies the collection to the new database and drops the source collection. See Naming Restrictions.
dropTarget boolean Optional.可选。If true, mongod will drop the target of renameCollection prior to renaming the collection. The default value is false.
writeConcern document

Optional.可选。A document that expresses the write concern for the operation. Omit to use the default write concern.

When issued on a sharded cluster, mongos converts the write concern of the renameCollection command and its helper db.collection.renameCollection() to "majority".

Note

You cannot rename a sharded collection. You can however rename an unsharded collection in a sharded cluster.

comment any

Optional.可选。A user-provided comment to attach to this command. Once set, this comment appears alongside records of this command in the following locations:

A comment can be any valid BSON type (string, integer, object, array, etc).

New in version 4.4.版本4.4中的新功能。

Behavior行为

Sharded Collections

renameCollection is not compatible with sharded collections.

Existing Target Collection

renameCollection fails if target is the name of an existing collection and you do not specify dropTarget: true.

Performance

Changed in version 3.6.在版本3.6中更改。

renameCollection has different performance implications depending on the target namespace.

If the target database is the same as the source database, renameCollection simply changes the namespace. This is a quick operation.

If the target database differs from the source database, renameCollection copies all documents from the source collection to the target collection. Depending on the size of the collection, this may take longer to complete.

Resource Locking

Changed in version 4.2.

If renaming a collection within the same database, renameCollection obtains an exclusive lock on the source and target collections for the duration of the operation. All subsequent operations on the collections must wait until renameCollection completes.

Prior to MongoDB 4.2, renaming a collection within the same database with renameCollection required an exclusive database lock.

If renaming a collection between different databases, renameCollection locking behavior depends on the MongoDB version:

  • For MongoDB 4.2.2 and later, renameCollection obtains an exclusive (W) lock on the target database, an intent shared (r) lock on the source database, and a shared (S) lock on the source collection. Subsequent operations on the target database must wait until renameCollection releases the exclusive database lock.
  • For MongoDB 4.2.1 and earlier, renameCollection obtains an exclusive (W) global lock. Subsequent operations on the mongod must wait until renameCollection releases the global lock.

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

local Database

  • You cannot rename a collection from a replicated database to the local database, which is not replicated.
  • You cannot rename a collection from the local database, which is not replicated, to a replicated database.

Open Cursors

Warning

The db.collection.renameCollection() method and renameCollection command will invalidate open cursors which interrupts queries that are currently returning data.

Change Streams

For Change Streams, the db.collection.renameCollection() method and renameCollection command create an invalidate Event for any existing Change Streams opened on the source or target collection.

Interaction with mongodump

A mongodump started with --oplog fails if a client issues the renameCollection command during the dump process. See mongodump.--oplog for more information.

Example示例

The following example renames a collection named orders in the test database to orders2014 in the test database.

db.adminCommand( { renameCollection: "test.orders", to: "test.orders2014" } )

The mongo shell provides the db.collection.renameCollection() helper for the command to rename collections within the same database. The following is equivalent to the previous example:

use test
db.orders.renameCollection( "orders2014" )

Exceptions

exception 10026:
 Raised if the source namespace does not exist.
exception 10027:
 Raised if the target namespace exists and dropTarget is either false or unspecified.
exception 15967:
 Raised if the target namespace is an invalid collection name.