Re: Deadlocks, editing context locking and network tasks
Re: Deadlocks, editing context locking and network tasks
- Subject: Re: Deadlocks, editing context locking and network tasks
- From: Mark Wardle <email@hidden>
- Date: Mon, 05 Sep 2016 19:06:28 +0100
Dear René,
Thank you. This is really helpful. I hadn’t spotted the screencast and will check it out.
Mark
> On 5 Sep 2016, at 09:34, René Bock <email@hidden> wrote:
>
> Hi Mark
>
>> Am 03.09.2016 um 22:36 schrieb Mark Wardle <email@hidden>:
>>
>> Dear all,
>>
>> I’m debugging a deadlock and realise that I probably need to re-design some of my code logic.
>>
>> Am I right in saying…
>>
>> 1. For a background thread, it is appropriate to create a new editing context (ERXEC.newEditingContext(osc)) using a dedicated and new object store coordinator (created using osc = new ERXObjectStoreCoordinator()).
>
> you should do that.
>
>>
>> 2. For a background thread, all such editing contexts should be lock()’ed and then unlock()’ed - unlocked in finally {} clause in case of uncaught exceptions. Automatic locking is only for ECs used within the R-R loop?
>
> yes
>
>>
>> 3. But what should one do if, either during a background thread, R-R loop (direct action or component action), one locks an editing context, does some processing of objects within that context, makes a network call, and then does some more processing within that context. Should one simply lock() and then hope for the best, or unlock, do the network process and then re-lock at the end. Are there any issues running unlock() if the EC isn’t actually locked? What happens if that network call never returns?
>
> You should handle network time-outs ;-) How long may the remote call may take? Seconds, minutes or hours? If you have many background tasks waiting network I/O, you may run out of OSCs or memory..
>
>
>>
>> 4. Is locking an EC from a newly created OSC completely independent from all other OSC ECs?
>
> If you lock en EC, the other OSC (and theire ECs) are not affected
>
>> If that lock isn’t released for some time, does it matter?
>
> see above.
>
>>
>> All advice appreciated,
>
>
> By the way: there is a very helpful screencast on wocummunity:
>
> http://www.wocommunity.org/podcasts/wowodc/2011/BackgroundTasks.mov
>
>
> Best regards
>
> René Bock
>
> --
> Phone: +49 69 650096 18
>
> salient GmbH, Lindleystraße 12, 60314 Frankfurt
> Main: +49 69 65 00 96 0 | http://www.salient-doremus.de
>
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