$currentOp (aggregation)¶

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Definition
Constraints
Example
Output Fields

Definition¶

New in version 3.6.

$currentOp¶

Returns a stream of documents containing information on active and/or dormant operations as well as inactive sessions that are holding locks as part of a transaction. The stage returns a document for each operation or session. To run $currentOp, use the db.aggregate() helper on the admin database.

The $currentOp aggregation stage is preferred over the currentOp command and its mongo shell helper db.currentOp(). Because currentOp command and db.currentOp() helper returns the results in a single document, the total size of the currentOp result set is subject to the maximum 16MB BSON size limit for documents. The $currentOp stage returns a cursor over a stream of documents, each of which reports a single operation. Each operation document is subject to the 16MB BSON limit, but unlike the currentOp command, there is no limit on the overall size of the result set.

$currentOp also enables you to perform arbitrary transformations of the results as the documents pass through the pipeline.

$currentOp takes an options document as its operand:

Changed in version 4.0.

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{ $currentOp: { allUsers: <boolean>, idleConnections: <boolean>, idleSessions: <boolean>, localOps: <boolean> } }

Option	Description
`allUsers`	Boolean. If set to `false`, `$currentOp` will only report operations belonging to the user who ran the command. If set to `true`, `$currentOp` will report operations belonging to all users. Note The `inprog` privilege is necessary to run `$currentOp` with `{ allUsers : true }`. Defaults to `false`.
`idleConnections`	Boolean. If set to `false`, `$currentOp` will only report active operations. If set to `true`, all operations including idle connections will be returned. Defaults to `false`.
`idleSessions`	Boolean. If set to `true`, then in addition to reporting on the active/dormant operations, `$currentOp` returns information on inactive sessions that are holding locks as part of a transaction. Each inactive session will appear as a separate document in the `$currentOp` stream. The document for a session includes information on the session id in the `lsid` field and the transaction in the `transaction` field. If set to `false`, `$currentOp` will not report on inactive sessions. Defaults to `true`. New in version 4.0.
`localOps`	Boolean. If set to `true` for an aggregation running on `mongos`, `$currentOp` reports only those operations running locally on that `mongos`. If `false`, then the `$currentOp` will instead report operations running on the shards. The `localOps` parameter has no effect for `$currentOp` aggregations running on `mongod`. Defaults to `false`. New in version 4.0.

Omitting any of the above parameters will cause $currentOp to use that parameter’s default value. Specify an empty document, as shown below, to use the default values of all parameters.

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{ $currentOp: { } }

Constraints¶

$currentOp must be the first stage in the pipeline.
Pipelines that start with $currentOp can only be run on the admin database.
On a standalone or replica set with authentication enabled, the inprog privilege is required to run $currentOp if the allUsers parameter is set to true.
On a sharded cluster, the inprog privilege is required to run all $currentOp pipelines.
$currentOp is not allowed in transactions.

Example¶

The following example returns information on inactive sessions that are holding locks as part of a transaction. Specifically:

The first stage returns documents for all active operations as well as inactive sessions that are holding locks as part of a transaction.
The second stage filters for just those documents related to inactive sessions that are holding locks as part of a transaction.

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db.getSiblingDB("admin").aggregate( [
   { $currentOp : { allUsers: true, idleSessions: true } },
   { $match : { active: false, transaction : { $exists: true } } }
] )

The operation returns documents of the form:

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{
   "host" : "example.mongodb.com:27017",
   "desc" : "inactive transaction",
   "client" : "198.51.100.1:53809",
   "connectionId" : NumberLong(40),
   "appName" : "",
   "clientMetadata" : {
      "driver" : {
         "name" : "PyMongo",
         "version" : "3.7.2"
      },
      "os" : {
         "type" : "Darwin",
         "name" : "Darwin",
         "architecture" : "x86_64",
         "version" : "10.14.2"
      },
      "platform" : "CPython 3.7.1.final.0"
   },
   "lsid" : {
      "id" : UUID("02039c77-3f05-4dd6-a42d-d2168a73fc95"),
      "uid" : BinData(0,"47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=")
   },
   "transaction" : {
      "parameters" : {
         "txnNumber" : NumberLong(1),
         "autocommit" : false,
         "readConcern" : {
            "level" : "snapshot"
         }
      },
      "readTimestamp" : Timestamp(1548869277, 3),
      "startWallClockTime" : "2019-01-30T12:28:06.979-0500",
      "timeOpenMicros" : NumberLong(34930476),
      "timeActiveMicros" : NumberLong(210),
      "timeInactiveMicros" : NumberLong(34930266),
      "expiryTime" : "2019-01-30T12:29:06.979-0500"
   }
   "waitingForLock" : false,
   "active" : false,
   "locks" : {
      "Global" : "w",
      "Database" : "w",
      "Collection" : "w"
   },
   "lockStats" : {
      "Global" : {
         "acquireCount" : {
            "r" : NumberLong(2),
            "w" : NumberLong(1)
         }
      },
      "Database" : {
         "acquireCount" : {
            "r" : NumberLong(1),
            "w" : NumberLong(1)
         }
      },
      "Collection" : {
         "acquireCount" : {
            "r" : NumberLong(1),
            "w" : NumberLong(1)
         }
      }
   }
}

Output Fields¶

Each output document may contain a subset of the following fields as relevant for the operation:

$currentOp.host¶: The name of the host against which the operation is run.

$currentOp.shard¶

The name of the shard where the operation is running.

Only present for sharded clusters.

$currentOp.desc¶: A description of the operation.

$currentOp.connectionId¶: An identifier for the connection where the specific operation originated.

$currentOp.client¶

The IP address (or hostname) and the ephemeral port of the client connection where the operation originates.

For multi-document transactions, $currentOp.client stores information about the most recent client to run an operation inside the transaction.

For standalones and replica sets only

$currentOp.client_s¶

The IP address (or hostname) and the ephemeral port of the mongos where the operation originates.

For sharded clusters only

$currentOp.clientMetadata¶

Additional information on the client.

For multi-document transactions, $currentOp.client stores information about the most recent client to run an operation inside the transaction.

$currentOp.appName¶: New in version 3.4.

The identifier of the client application which ran the operation. Use the appName connection string option to set a custom value for the appName field.

$currentOp.active¶: A boolean value specifying whether the operation has started. Value is true if the operation has started or false if the operation is idle, such as an idle connection, an inactive session, or an internal thread that is currently idle. An operation can be active even if the operation has yielded to another operation.

$currentOp.currentOpTime¶: The start time of the operation.

New in version 3.6.

$currentOp.opid¶: The identifier for the operation. You can pass this value to db.killOp() in the mongo shell to terminate the operation.

Warning

Terminate running operations with extreme caution. Only use db.killOp() to terminate operations initiated by clients and do not terminate internal database operations.

$currentOp.secs_running¶

The duration of the operation in seconds. MongoDB calculates this value by subtracting the current time from the start time of the operation.

Only present if the operation is running; i.e. if active is true.

$currentOp.microsecs_running¶

The duration of the operation in microseconds. MongoDB calculates this value by subtracting the current time from the start time of the operation.

Only present if the operation is running; i.e. if active is true.

$currentOp.lsid¶

The session identifier.

Only present if the operation is associated with a session.

New in version 3.6.

$currentOp.transaction¶

A document that contains multi-document transaction information.