The SIO2 project
  1. The SIO2 project
  2. SIO-1583

Refactor unpackmgr to run asynchronously with sioworkers

        Details

        • Type: Improvement Improvement
        • Status: Closed Closed
        • Priority: Minor Minor
        • Resolution: Fixed
        • Affects Version/s: Near Future
        • Fix Version/s: None
        • Component/s: OIOIOI
        • Labels:
          None

          Description

          In Celery 3.2 it won't be possible for a Celery task (in particular, unpackmgr_job) to block and wait for a result coming from another task (that is, call get(); in this case, unpackmgr_job waits for sioworkers to finish). If Celery 3.2 is going to be used, the unpack manager needs to be rewritten.

            Activity

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            Kamil Braun made changes -
            Field Original Value New Value
            Fix Version/s Sprint 2/2014 [ 12004 ]
            Kamil Braun made changes -
            Summary Fix a deadlock in the unpackmgr_job Celery task Refactor unpackmgr to run asynchronously with sioworkers
            Issue Type Bug [ 1 ] Improvement [ 4 ]
            Fix Version/s Sprint 2/2014 [ 12004 ]
            Affects Version/s Near Future [ 11001 ]
            Affects Version/s Current Version [ 11000 ]
            Priority Major [ 3 ] Minor [ 4 ]
            Description The following situation leads to a deadlock:
            1. A worker is spawned in which the unpackmgr_job Celery task begins to be processed. The worker pool is now exhausted - no more workers can be spawned.
            2. unpackmgr_job calls sio.workers.run asynchronously. The sio.workers task doesn't start, since it waits for a worker to be available from the pool.
            3. unpackmgr_job calls get() on the async task. It blocks, waiting for the result.
            4. ...
            5. No profit.

            Tested: when using Django 1.6 with the Django database as a Celery broker, the deadlock actually happens. RabbitMQ works, but still, this is a major bug and needs to be fixed.             		In Celery 3.2 it won't be possible for a Celery task (in particular, unpackmgr_job) to block and wait for a result coming from another task (that is, call get(); in this case, unpackmgr_job waits for sioworkers to finish). If Celery 3.2 is going to be used, the unpack manager needs to be rewritten.
            Sebastian Jaszczur made changes -
            Status New [ 10000 ] Resolved [ 5 ]
            Assignee Szymon Acedański [ accek ]
            Resolution Fixed [ 1 ]
            Szymon Acedański made changes -
            Status Resolved [ 5 ] Closed [ 6 ]

              People

              • Assignee:
                Szymon Acedański
                Reporter:
                Kamil Braun
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                Dates

                • Created:
                  Updated:
                  Resolved: