Re: Sketch of extending error handling for subtransactions

I agree we don't want to add a savepoint on top of the exceptions as you
stated below.

I am _still_ unclear on what still needs to be done to complete NT and
PITR. Are you more aware of the open issues?

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Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > So it allows functions to use subtransactions and recover from errors.
> > I thought that was more than we could do for 7.5 and in fact the release
> > notes now saw that will be done in a future release.
>
> I think there's only a day or two's work between here and there, and it
> would be foolish not to have the feature if we can get it.
>
> As I see it, we need:
>
> 1. The elog.c factoring described in this thread.
>
> 2. An extension to the SPI API to allow execution of commands within
> a subtransaction, with catching of errors.
>
> 3. A bit of work on plpgsql to support some kind of EXCEPTION syntax.
>
> I might decide to forget about SPI and trap errors directly in plpgsql,
> but in any case it doesn't seem out of reach.
>
> I was just looking around the net to see exactly what Oracle's PL/SQL
> syntax is. It doesn't seem too unreasonable syntax-wise:
>
> BEGIN
> ... controlled statements ...
> EXCEPTION
> WHEN exception_name THEN
> ... error handling statements ...
> WHEN exception_name THEN
> ... error handling statements ...
> ...
> WHEN OTHERS THEN
> ... error handling statements ...
> END;
>
> There's nothing here we couldn't do. However, it seems that Oracle
> thinks you should throw in explicit SAVEPOINT and ROLLBACK statements
> on top of this! That's just weird. It might be that we should
> deliberately *not* adopt the exact syntax they are using, just so we
> don't create compatibility gotchas.
>
> regards, tom lane
>
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