MongoDB Cluster Parameters

Synopsis

You can specify configuration options which affect all nodes in a replica set or sharded cluster. To set these options, use the setClusterParameter command:

db.adminCommand( { setClusterParameter:{ <parameter>: <value> } } )

To view the current values of cluster parameters, use the getClusterParameter command:

db.adminCommand( { getClusterParameter: <parameter> } )

The setClusterParameter command is only available in self-managed installations. The setClusterParameter command is not available in MongoDB Atlas.

Parameters

changeStreamOptions

New in version 6.0.

Available for both mongod and mongos.

This is an object containing change stream configuration options.

You can only set changeStreamOptions on mongos or a replica set primary. The value is set cluster-wide.

changeStreamOptions.preAndPostImages.expireAfterSeconds

New in version 6.0.

Default: off

Controls the retention policy of change stream pre- and post-images. Pre- and post-images are the versions of a document before and after document modification respectively. expireAfterSeconds controls how long pre- and post-images are retained.

When expireAfterSeconds is off, MongoDB uses the default retention policy: pre- and post-images are retained until the corresponding change stream events are removed from the oplog.

To specify the minimum pre- and post-image retention time:

• Set expireAfterSeconds using an integer.

• If a change stream event is removed from the oplog, then the corresponding pre- and post-images are also deleted regardless of the expireAfterSeconds pre- and post-image retention time.

The following example sets the retention time for pre- and post-images in change streams to 100 seconds:

db.runCommand( {
   setClusterParameter: {
   changeStreamOptions: { preAndPostImages: { expireAfterSeconds: 100 } }
   }
} )