Try too see if in production there is a transaction that stays open for a
long time.
It could be a console left open somewhere?
2015-02-27 8:42 GMT+01:00 Osman Masood <oamas...@gmail.com>:
> Right. The purpose of using the console was to simulate what actually
> happens in production.
>
> On Thu, Feb 26, 2015 at 11:39 PM, Niphlod <niph...@gmail.com> wrote:
>
>> you know that on console, after queue_task() you need to commit(), right
>> ? If you leave the transaction hanging, no wonder that you're observing
>> deadlocks!
>>
>>
>> On Friday, February 27, 2015 at 3:38:19 AM UTC+1, Osman Masood wrote:
>>>
>>> I was actually able to easily reproduce this. Just open up 2 web2py
>>> consoles (which connect to the same DB), and do:
>>>
>>> scheduler.queue_task('myfunc', pvars=dict(), immediate=True)
>>>
>>> The first one will succeed, and the second one will hang there for some
>>> time, and then give the deadlock exception above.
>>>
>>> This kinda makes sense, looking at the above DB query & considering
>>> record-level locking. We have conditional writes on all records in the
>>> scheduler_worker table, so if two connections attempt this at the same
>>> time, it would follow that there is a deadlock. (Correct me if I'm wrong.)
>>> So I think the solution would be something like (on line 1303 of
>>> scheduler.py):
>>>
>>> if immediate:
>>>
>>> - self.db(self.db.scheduler_worker.is_ticker ==
>>> True).update(status=PICK)
>>>
>>> + scheduler_worker_tickers =
>>> self.db(self.db.scheduler_worker.is_ticker
>>> == True).select()
>>>
>>> + for scheduler_worker_ticker in scheduler_worker_tickers:
>>>
>>> + scheduler_worker_ticker.update_record(status=PICK)
>>>
>>>
>>> On Thursday, February 26, 2015 at 3:54:47 PM UTC-8, Osman Masood wrote:
>>>>
>>>> Thanks for the quick response!
>>>>
>>>> I'm using Amazon RDS (just basically MySQL), on a pretty beefy instance
>>>> (db.m3.large), 1000 IOPS. Would be pretty surprised if that were the
>>>> problem.
>>>>
>>>> Running 5 scheduler workers with the default heartbeat (3s).
>>>>
>>>> On Thursday, February 26, 2015 at 3:35:41 PM UTC-8, Niphlod wrote:
>>>>>
>>>>> it seems to me that there is database contention........ although the
>>>>> exception **should** be trapped (i.e. try to set the status to "PICK", if
>>>>> not, well.... it's not a fatal error), there's something wrong with your
>>>>> setup or your database is too much "underpowered" to do what you're
>>>>> asking.
>>>>> How many workers are running and with what heartbeat ?
>>>>>
>>>>> On Friday, February 27, 2015 at 12:28:28 AM UTC+1, Osman Masood wrote:
>>>>>>
>>>>>> Hello all,
>>>>>>
>>>>>> I keep getting this error when calling scheduler.queue_task() with
>>>>>> immediate=True:
>>>>>>
>>>>>> <class 'gluon.contrib.pymysql.err.InternalError'> (1213, u'Deadlock
>>>>>> found when trying to get lock; try restarting transaction')
>>>>>>
>>>>>> The stack trace shows this is the culprit:
>>>>>>
>>>>>> self.db(self.db.scheduler_worker.is_ticker == True).update(status=PICK)
>>>>>>
>>>>>> (This is a web application which uses the scheduler pretty extensively.)
>>>>>> Seems like multiple connections are competing for access to the same
>>>>>> scheduler_worker row.
>>>>>>
>>>>>> Seems to me like a web2py bug. Any help would be greatly appreciated.
>>>>>> Thanks!
>>>>>>
>>>>>> --
>> Resources:
>> - http://web2py.com
>> - http://web2py.com/book (Documentation)
>> - http://github.com/web2py/web2py (Source code)
>> - https://code.google.com/p/web2py/issues/list (Report Issues)
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>
> --
> Resources:
> - http://web2py.com
> - http://web2py.com/book (Documentation)
> - http://github.com/web2py/web2py (Source code)
> - https://code.google.com/p/web2py/issues/list (Report Issues)
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--
Resources:
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- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
- https://code.google.com/p/web2py/issues/list (Report Issues)
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