Re: PG_TRY & PG_CATCH in FDW development

Thanks for the reply.

On Tue, Apr 25, 2017 at 7:45 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Abbas Butt <abbas(dot)butt(at)enterprisedb(dot)com> writes:
> > What is happening for me is that PG_RE_THROW takes me to PG_TRY in the
> same
> > function and then PG_TRY jumps to PG_CATCH where PG_RE_THROW again jumps
> to
> > PG_TRY in the same function resulting in an infinite loop. The query
> > therefore never returns. It is supposed to throw the error and quit.
>
> Apparently PG_exception_stack isn't getting restored properly, but it's
> sure hard to see why. I'm suspicious that you have something silly like
> mismatched braces in the vicinity of the TRY/CATCH structure.
>

I rechecked, braces are matching.

>
> FWIW, doing things like disconnecting remote sessions might be better
> handled in transaction-cleanup logic, anyway.

I see that postgres_fdw is using a similar login in pgfdw_xact_callback.
Let me try and use the same technique.

> What covers you for that
> if the query aborts while control is not within your PG_TRY block?
>

All the code that requires a connection to the foreign server is with in
the PG_TRY block, it is therefore not required any where else to close
connection before reporting any error.

>
> regards, tom lane
>

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