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db.killOp()

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  • Description
  • Sharded Cluster
  • Access Control
db.killOp(opid)

Terminates an operation as specified by the operation ID. To find operations and their corresponding IDs, see $currentOp or db.currentOp().

The db.killOp() method has the following parameter:

Parameter
Type
Description
op
number
An operation ID.

Warning

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

The db.killOp() method can be run on a mongos and can kill queries (read operations) that are running on more than one shard in a cluster.

For example, to kill a query operation on a sharded cluster:

  1. On the same mongos where the client issued the query, find the opid of the query operation to kill by running the aggregation pipeline $currentOp with the localOps: true:

    use admin
    db.aggregate( [
    { $currentOp : { allUsers: true, localOps: true } },
    { $match : <filter condition> } // Optional. Specify the condition to find the op.
    // e.g. { op: "getmore", "command.collection": "someCollection" }
    ] )

    Important

    You must issue this aggregation operation on the same mongos where the client issued the query.

  2. Once you find the query operation to kill, issue db.killOp() with the opid on the mongos:

    db.killOp(<opid of the query to kill>)

Tip

See also:

The localOps parameter in $currentOp.

Alternatively, you can find and kill the read operation from a shard member where the operation is running. MongoDB propagates the kill operation to the other shards and mongos instances:

  1. On one of the shards where the operation is running, find the opid of the query operation to kill:

    use admin
    db.aggregate( [
    { $currentOp : { allUsers: true } },
    { $match : <filter condition> } // Optional. Specify the condition to find the op.
    // e.g. { op: "getmore", "command.collection": "someCollection" }
    ] )
  2. Once you find the query operation to kill, issue db.killOp() with the opid on the shard member:

    db.killOp(<opid of the query to kill>)

    MongoDB propagates the kill operation to the other shards and mongos instances.

Within a Session

MongoDB drivers associate all operations with a server session, with the exception of unacknowledged writes.

If the write operation is associated with a session, you can use the killSessions command on the mongos to kill the write operation across shards.

  1. Run the aggregation pipeline $currentOp on the mongos to find the lsid (logical session id).

    use admin
    db.aggregate( [
    { $currentOp : { allUsers: true, localOps: true } },
    { $match : <filter condition> } // Optional. Specify the condition to find the op.
    // e.g. { "op" : "update", "ns": "mydb.someCollection" }
    ] )
    1. Using the returned lsid information, issue the killSessions command on the mongos to kill the operation on the shards.

      db.adminCommand( { killSessions: [
      { "id" : UUID("80e48c5a-f7fb-4541-8ac0-9e3a1ed224a4"), "uid" : BinData(0,"47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=") }
      ] } )
Without a Session

If the write operation is not associated with a session, you must find and kill the operation on all the shards associated with the write.

  1. From a mongos, run the aggregation pipeline $currentOp to find the opid(s) of the query operation on the shards:

    use admin
    db.aggregate( [
    { $currentOp : { allUsers: true } },
    { $match : <filter condition> } // Optional. Specify the condition to find the op.
    ] )

    When run on a mongos, $currentOp returns the opids in the format of "<shardName>:<opid on that shard>"; e.g.

    {
    "shard" : "shardB",
    ..
    "opid" : "shardB:79214",
    ...
    },
    {
    "shard" : "shardA",
    ..
    "opid" : "shardA:100913",
    ...
    },
  2. Using the opid information, issue db.killOp() on the mongos to kill the operation on the shards.

    db.killOp("shardB:79014");
    db.killOp("shardA:100813");

On systems running with authorization, to kill operations not owned by the user, the user must have access that includes the killop privilege action.

On mongod instances, users can kill their own operations even without the killop privilege action.

Tip

See also:

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