CODEWITHSUNDEEP
mongodb
silviud
silviud

Reputation: 1025

How do you get MongoDB locks info per collection

Is there a way way to get the locks statistics per collection in MongoDB 3.x ? This info is not present into the

 db.serverStatus()

Ideally I would retain the collection names as well.

Upvotes: 1

Views: 7492

Answers (2)

Cydrick Trudel
Cydrick Trudel

Reputation: 10497

The db.currentOp() command should give you more insight about locks due to currently running operations.

Here's a sample output of the command:

On query:

{
    "locks": {"^myDB": "R"},
    "ns": "myDB.bar",
    "op": "query",
    "opid": 1349152,
    "query": {"test": 1},
    "secs_running": 15,
    "waitingForLock": true
 }

On update:

  {
    "locks": {
      "^": "w",
      "^local": "W",
      "^myDB": "W"
    },
    "ns": "myDB.bar",
    "op": "update",
    "opid": 1344808,
    "query": {},
    "secs_running": 53,
    "waitingForLock": false
  }

I haven't tested it, but something like this should get the locks for a collection:

db.currentOp(
    {
        $and: [ 
            {"waitingForLock" : true},
            {"ns" : "mydb.mycoll"}
        ]
    }
)

Source: http://blog.mlab.com/2014/02/mongodb-currentop-killop/

Upvotes: 4

Saleem
Saleem

Reputation: 8988

Try looking at:

"locks" : {
    "Global" : {
        "acquireCount" : {
            "r" : NumberLong(5776),
            "w" : NumberLong(14),
            "W" : NumberLong(4)
        }
    },
    "Database" : {
        "acquireCount" : {
            "r" : NumberLong(2872),
            "w" : NumberLong(1),
            "R" : NumberLong(7),
            "W" : NumberLong(13)
        }
    },
    "Collection" : {     <-------------- see collection locks
        "acquireCount" : {  
            "r" : NumberLong(2735)
        }
    },

For more information visit Collection locks at MongoDB website

Upvotes: 1

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