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> } )

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 } }
   }
} )