$listLocalSessions（聚合阶段）

定义

$listLocalSessions

列出由mongod或mongos实例在内存中缓存的会话。

重要

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.

该阶段采用以下语法：

{ $listLocalSessions: <document> }

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

字段	说明
{ }	如果使用访问控制运行，则返回当前经过身份验证的用户的所有会话。 如果在没有访问控制的情况下运行，则返回所有会话。
{ users: [ { user: <user>, db: <db> }, ... ] }	返回指定用户的所有会话。 如果使用访问控制运行，则经过身份验证的用户必须具有对集群执行listSessions操作的权限，才能列出其他用户的会话。
{ allUsers: true }	返回所有用户的所有会话。 如果使用访问控制运行，则经过身份验证的用户必须具有对集群执行listSessions操作的权限。

限制

$listLocalSessions 不允许在事务中使用。

示例

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

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

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

const pipeline = [{ $listLocalSessions: { allUsers: true } }];
const cursor = db.aggregate(pipeline);
return cursor;

const pipeline = [
  { 
    $listLocalSessions: { 
      users: [{ user: "myAppReader", db: "test"}] 
    } 
  }
];
const cursor = db.aggregate(pipeline);
return cursor;

const pipeline = [{ $listLocalSessions: {} }];
const cursor = db.aggregate(pipeline);
return cursor;

输出

$listLocalSessions 返回一个游标，其中每个文档在内存中缓存一个会话。每个文档都有以下原型：

{
   _id: {
      id: <UUID>,
      uid: <BinData>
   },
   lastUse: <date>
}