Mongo.setWriteConcern()¶

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Definition
Syntax
Example

Definition¶

Mongo.setWriteConcern()¶

Sets the write concern for the Mongo() connection object.

See the Write Concern for an introduction to write concerns in MongoDB.

Syntax¶

The command takes the following form:

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db.getMongo().setWriteConcern( { w: <value>, j: <boolean>, wtimeout: <number> } )

The fields are:

Field Description

w

The number of mongod or mongod instances that must acknowledge a write. Possible values are:

“majority”. A majority of the target instances must acknowledge the write.
<number>. The specified number of target instances must acknowledge the write.
<custom write concern name>. A user defined write concern, the tagged instances must acknowledge the write.

See write concern specification for details.

j A boolean value. j: true requests acknowledgment that the write operation has been written to the on-disk journal.

wtimeout The number of milliseconds to wait for acknowledgement of the write concern. wtimeout is only applicable when w has a value greater than 1.

Example¶

In the following example:

Two mongod or mongod instances must acknowledge writes.
There is a 1 second timeout to wait for write acknowledgements.

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db.getMongo().setWriteConcern( { w: 2, wtimeout: 1000 } )