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: René Bock <email@hidden>
- Date: Mon, 05 Sep 2016 08:34:59 +0000
- Thread-topic: Deadlocks, editing context locking and network tasks
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
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Main: +49 69 65 00 96 0 | http://www.salient-doremus.de
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