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- cloneCollection
cloneCollection¶
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Definition¶
-
cloneCollection
¶ Copies a collection from a remote
mongod
instance to the currentmongod
instance.cloneCollection
creates a collection in a database with the same name as the remote collection’s database.cloneCollection
takes the following form:cloneCollection
has the following fields:Field Type Description cloneCollection
string The namespace of the collection to copy. The namespace is a combination of the database name and the name of the collection. from
string The address of the server to clone from. query
document Optional. A query that filters the documents in the source collection that cloneCollection
will copy to the current database.writeConcern
document Optional. A document that expresses the write concern for the operation. Omit to use the default write concern. bypassDocumentValidation
boolean Optional. Enables
cloneCollection
to bypass document validation during the operation. This lets you insert documents that do not meet the validation requirements.New in version 3.2.
The mongo shell provides the method
db.cloneCollection()
as a wrapper for thecloneCollection
command.
Behavior¶
mongos
¶
mongos
does not support cloneCollection
.
Authorization¶
cloneCollection
cannot be used if the from server has
authorization enabled.
Namespace¶
Changed in version 3.0.
If the given namespace already exists in the destination
mongod
instance, cloneCollection
will return an
error.
FeatureCompatibilityVersion¶
You cannot copy data between a MongoDB 4.0 mongod
instance with featureCompatibilityVersion (FCV) 4.0
and a MongoDB version 3.6 mongod
instance.
Note
You cannot copy data between a MongoDB 4.0 mongod
instance (regardless of the FCV value) and a MongoDB 3.4 and earlier
mongod
instance.
For example:
Instance 1 | Instance 2 | |
---|---|---|
Version 4.0 mongod with FCV 4.0 |
Version 4.0 mongod with FCV 4.0 |
Can copy data. |
Version 4.0 mongod with FCV 4.0 |
Version 4.0 mongod with FCV 3.6 |
Can copy data. |
Version 4.0 mongod with FCV 4.0 |
Version 3.6 mongod with FCV 3.6 |
Cannot copy data. Instance 2 must be a MongoDB version 4.0 |
Version 4.0 mongod with FCV 3.6 |
Version 3.6 mongod with FCV 3.6 |
Can copy data. |
Version 4.0 mongod with FCV 3.6 |
Version 3.6 mongod with FCV 3.4 |
Can copy data. |
In general, if the mongod
instance has its
featureCompatibilityVersion (FCV) set to its MongoDB
version, you cannot copy data between that instance and a
mongod
instance of an earlier MongoDB version.
Operations that copy data include:
db.cloneCollection()
and the commandcloneCollection
db.cloneDatabase()
and the commandclone
db.copyDatabase()
and the commandcopydb
Example¶
This operation copies the profiles
collection from the users
database on the server at mongodb.example.net
into the users
database on the local server. The operation only
copies documents that satisfy the query { 'active' : true }
.