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currentOp

Definition

currentOp

Returns a document that contains information on in-progress operations for the mongod instance.

currentOp has the following form:

{ currentOp: 1 }

The mongo shell provides the db.currentOp() wrapper for the currentOp command.

Behavior

currentOp must run against the admin database, and it can accept several optional fields.

Field Description
"$ownOps"

Boolean. If set to true, returns information on the current user’s operations only.

On mongod instances, users are always authorized to run currentOp with "$ownOps": true to view their own operations. See access control.

New in version 3.2.9.

"$all"

Boolean. If set to true, returns information on all operations, including operations on idle connections and system operations.

"$all": true overrides any output field filters.

<filter> Specify filter conditions on the Output Fields. See Examples.

currentOp and the database profiler report the same basic diagnostic information for all CRUD operations, including the following:

These operations are also included in the logging of slow queries (see slowOpThresholdMs for more information about slow query logging).

Access Control

On systems running with authorization, the user must have access that includes the inprog privilege action.

Changed in version 3.2.9: On mongod instances, users can use $ownOps to view their own operations without the inprog privilege action.

db.adminCommand( { currentOp: 1, "$ownOps": 1 } )

Examples

The following examples use the currentOp command with various query documents to filter the output.

Display All Current Operations

db.adminCommand(
   {
     currentOp: true,
     "$all": true
   }
)

Write Operations Waiting for a Lock

The following example returns information on all write operations that are waiting for a lock:

db.adminCommand(
   {
     currentOp: true,
     "waitingForLock" : true,
     $or: [
        { "op" : { "$in" : [ "insert", "update", "remove" ] } },
        { "query.findandmodify": { $exists: true } }
    ]
   }
)

Active Operations with no Yields

The following example returns information on all active running operations that have never yielded:

db.adminCommand(
   {
     currentOp: true,
     "active" : true,
     "numYields" : 0,
     "waitingForLock" : false
   }
)

Active Operations on a Specific Database

The following example returns information on all active operations for database db1 that have been running longer than 3 seconds:

db.adminCommand(
   {
     currentOp: true,
     "active" : true,
     "secs_running" : { "$gt" : 3 },
     "ns" : /^db1\./
   }
)

Active Indexing Operations

The following example returns information on index creation operations:

db.adminCommand(
    {
      currentOp: true,
      $or: [
        { op: "command", "query.createIndexes": { $exists: true } },
        { op: "none", ns: /\.system\.indexes\b/ }
      ]
    }
)

Output Example

The following is a prototype of currentOp output.

{
  "inprog": [
       {
         "host" : <string>,
         "desc" : <string>,
         "connectionId" : <number>,
         "client" : <string>,
         "appName" : <string>,
         "clientMetadata" : <document>,
         "active" : <boolean>,
         "currentOpTime" : <string>,
         "opid" : <number>,
         "secs_running" : <NumberLong()>,
         "microsecs_running" : <number>,
         "op" : <string>,
         "ns" : <string>,
         "command" : <document>,
         "originatingCommand" : <document>,
         "planSummary": <string>,
         "msg": <string>,
         "progress" : {
             "done" : <number>,
             "total" : <number>
         },
         "killPending" : <boolean>,
         "numYields" : <number>,
         "locks" : {
             "Global" : <string>,
             "MMAPV1Journal" : <string>,
             "Database" : <string>,
             "Collection" : <string>,
             "Metadata" : <string>,
             "oplog" : <string>
         },
         "waitingForLock" : <boolean>,
         "lockStats" : {
             "Global": {
                "acquireCount": {
                   "r": <NumberLong>,
                   "w": <NumberLong>,
                   "R": <NumberLong>,
                   "W": <NumberLong>
                },
                "acquireWaitCount": {
                   "r": <NumberLong>,
                   "w": <NumberLong>,
                   "R": <NumberLong>,
                   "W": <NumberLong>
                },
                "timeAcquiringMicros" : {
                   "r" : NumberLong(0),
                   "w" : NumberLong(0),
                   "R" : NumberLong(0),
                   "W" : NumberLong(0)
                },
                "deadlockCount" : {
                   "r" : NumberLong(0),
                   "w" : NumberLong(0),
                   "R" : NumberLong(0),
                   "W" : NumberLong(0)
                }
             },
             "MMAPV1Journal": {
                ...
             },
             "Database" : {
                ...
             },
             ...
         }
       },
       ...
   ],
   "fsyncLock": <boolean>,
   "info": <string>
}

Output Fields

currentOp.desc

A description of the client. This string includes the connectionId.

currentOp.connectionId

An identifier for the connection where the operation originated.

currentOp.client

A string with information about where the operation originated.

currentOp.appName

A string with information about the type of client which made the request.

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.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 or an internal thread that is currently idle. An operation can be active even if the operation has yielded to another operation.

Changed in version 3.0: For some inactive background threads, such as an inactive signalProcessingThread, MongoDB suppresses various empty fields.

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 appears if the operation is running; i.e. if active is true.

currentOp.microsecs_running

New in version 2.6.

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

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

currentOp.op

A string that identifies the type of operation. The possible values are:

  • "none"
  • "update"
  • "insert"
  • "query"
  • "command"
  • "getmore"
  • "remove"
  • "killcursors"

"query" operations include read operations.

"command" operations include most commands such as the createIndexes and findandmodify.

Changed in version 3.0: Write operations that use the insert, update, and delete commands respectively display "insert", "update", and "remove" for op. Previous versions include these write commands under "query" operations.

Changed in version 3.2: Most commands including createIndexes and findandmodify display "command" for op. Previous versions of MongoDB included these commands under "query" operations.

currentOp.ns

The namespace the operation targets. A namespace consists of the database name and the collection name concatenated with a dot (.); that is, "<database>.<collection>".

currentOp.command

Changed in version 3.6.

A document containing the full command object associated with this operation. If the command document exceeds 1 kilobyte, the document has the following form:

"command" : {
  "$truncated": <string>,
  "comment": <string>
}

The $truncated field contains a string summary of the document excluding the document’s comment field if present. If the summary still exceeds 1 kilobyte then it is further truncated, denoted by an ellipsis (…) at the end of the string.

The comment field is present if a comment was passed to the operation.

The following example output contains the command object for a find operation on a collection named items in a database named test:

"command" : {
  "find" : "items",
  "filter" : {
    "sku" : 1403978
  },
  "$db" : "test"
}

The following example output contains the command object for a getMore operation generated by a command with cursor id 80336119321 on a collection named items in a database named test:

"command" : {
  "getMore" : NumberLong("80336119321"),
  "collection" : "items",
  "$db" : "test"
}
currentOp.originatingCommand

Changed in version 3.6: For "getmore" operations which retrieve the next batch of results from a cursor, the originatingCommand field contains the full command object (e.g. find or aggregate) which originally created that cursor.

currentOp.planSummary

A string that contains the query plan to help debug slow queries.

currentOp.client

The IP address (or hostname) and the ephemeral port of the client connection where the operation originates. If your inprog array has operations from many different clients, use this string to relate operations to clients.

currentOp.appName

New in version 3.4.

The identifier of the client application which ran the operation. If the operation was run in the MongoDB shell, the appName is always "MongoDB Shell". If the operation originated from a driver, appName may be set to a custom string.

currentOp.locks

Changed in version 3.0.

The locks document reports the type and mode of locks the operation currently holds. The possible lock types are as follows:

Lock Type Description
Global Represents global lock.
MMAPV1Journal Represents MMAPv1 storage engine specific lock to synchronize journal writes; for non-MMAPv1 storage engines, the mode for MMAPV1Journal is empty.
Database Represents database lock.
Collection Represents collection lock.
Metadata Represents metadata lock.
oplog Represents lock on the oplog.

The possible modes are as follows:

Lock Mode Description
R Represents Shared (S) lock.
W Represents Exclusive (X) lock.
r Represents Intent Shared (IS) lock.
w Represents Intent Exclusive (IX) lock.
currentOp.waitingForLock

Returns a boolean value. waitingForLock is true if the operation is waiting for a lock and false if the operation has the required lock.

currentOp.msg

The msg provides a message that describes the status and progress of the operation. In the case of indexing or mapReduce operations, the field reports the completion percentage.

currentOp.progress

Reports on the progress of mapReduce or indexing operations. The progress fields corresponds to the completion percentage in the msg field. The progress specifies the following information:

currentOp.progress.done

Reports the number completed.

currentOp.progress.total

Reports the total number.

currentOp.killPending

Returns true if the operation is currently flagged for termination. When the operation encounters its next safe termination point, the operation will terminate.

currentOp.numYields

numYields is a counter that reports the number of times the operation has yielded to allow other operations to complete.

Typically, operations yield when they need access to data that MongoDB has not yet fully read into memory. This allows other operations that have data in memory to complete quickly while MongoDB reads in data for the yielding operation.

currentOp.fsyncLock

Specifies if database is currently locked for fsync write/snapshot.

Only appears if locked; i.e. if fsyncLock is true.

currentOp.info

Information regarding how to unlock database from db.fsyncLock(). Only appears if fsyncLock is true.

currentOp.lockStats

For each lock type and mode (see currentOp.locks for descriptions of lock types and modes), returns the following information:

currentOp.lockStats.acquireCount

Number of times the operation acquired the lock in the specified mode.

currentOp.lockStats.acquireWaitCount

Number of times the operation had to wait for the acquireCount lock acquisitions because the locks were held in a conflicting mode. acquireWaitCount is less than or equal to acquireCount.

currentOp.lockStats.timeAcquiringMicros

Cumulative time in microseconds that the operation had to wait to acquire the locks.

timeAcquiringMicros divided by acquireWaitCount gives an approximate average wait time for the particular lock mode.

currentOp.lockStats.deadlockCount

Number of times the operation encountered deadlocks while waiting for lock acquisitions.

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