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Aggregation Pipeline Stages

$listLocalSessions

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  • Definition
  • Restrictions
  • Examples

Definition

$listLocalSessions

Lists the sessions cached in memory by the mongod or mongos instance.

Important

When a user creates a session on a mongod or mongos instance, the record of the session initially exists only in-memory on the instance; i.e. the record is local to the instance. Periodically, the instance will sync its cached sessions to the system.sessions collection in the config database, at which time, they are visible to $listSessions and all members of the deployment. Until the session record exists in the system.sessions collection, you can only list the session via the $listLocalSessions operation.

The $listLocalSessions operation uses the db.aggregate() method and not the db.collection.aggregate().

To run $listLocalSessions, it must be the first stage in the pipeline.

The stage has the following syntax:

{ $listLocalSessions: <document> }

The $listLocalSessions stage takes a document with one of the following contents:

Field
Description
{ }

If running with access control, returns all sessions for the current authenticated user.

If running without access control, returns all sessions.

{ users: [ { user: <user>, db: <db> }, ... ] }
Returns all sessions for the specified users. If running with access control, the authenticated user must have privileges with listSessions action on the cluster to list sessions for other users.
{ allUsers: true }
Returns all sessions for all users. If running with access control, the authenticated user must have privileges with listSessions action on the cluster.

Restrictions

$listLocalSessions is not allowed in transactions.

Examples

List All Local Sessions

From the connected mongod / mongos instance's in-memory cache of sessions, the following aggregation operation lists all sessions:

Note

If running with access control, the current user must have privileges with listSessions action on the cluster.

db.aggregate( [  { $listLocalSessions: { allUsers: true } } ] )

List All Local Sessions for the Specified Users

From the connected mongod / mongos instance's in-memory cache, the following aggregation operation lists all the sessions for the specified user myAppReader@test:

Note

If running with access control and the current user is not the specified user, the current user must have privileges with listSessions action on the cluster.

db.aggregate( [ { $listLocalSessions: { users: [ { user: "myAppReader", db: "test" } ] } } ] )

List All Local Sessions for the Current User

From the connected mongod / mongos instance's in-memory cache, the following aggregation operation lists all sessions for the current user if run with access control:

db.aggregate( [ { $listLocalSessions: { } } ] )

If run without access control, the operation lists all local sessions.

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