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Re: Cancellation and wc-ng txns

From: Branko ─îibej <brane_at_e-reka.si>
Date: Fri, 22 Apr 2011 23:20:29 +0200

On 22.04.2011 23:11, Hyrum K Wright wrote:
> What's the relationship between cancellation functions and
> transactions in wc-ng?
>
> In the interests of performance and correctness, we've been moving
> toward a model where more and more gets done in a single wc-ng
> transaction. I've no problem with that, and like the atomicity and
> speed it gives us, but how does that interact with our cancellation
> functions? Do we still check for cancellation from within the
> transaction? If the user cancels, do we rollback the transaction, or
> commit it?
>
> My question then is two-fold:
> * what actually happens today?
> * and what is the Right Thing to happen?
>
> My own thoughts: we should check for cancellation, and if it occurs,
> we should rollback the txn.

If the transaction is so long-running that cancellation checks would
make sense ... then something's wrong, as AFAIUI long-running
transactions are frowned upon around here. Still, if that does happen,
then the only thing you can do when an operation is canceled is to roll
back the transaction -- anything else would be bound to produce invalid
state in the database.

-- Brane
Received on 2011-04-22 23:21:02 CEST

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