From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michel Pelletier <pelletier.michel@gmail.com>
cc: pgsql-general <pgsql-general@lists.postgresql.org>
Subject: Re: Using Expanded Objects other than Arrays from plpgsql
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Comments: In-reply-to Michel Pelletier <pelletier.michel@gmail.com>
	message dated "Sun, 20 Oct 2024 20:29:13 -0700"
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Date: Sun, 20 Oct 2024 23:46:44 -0400
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Michel Pelletier <pelletier.michel@gmail.com> writes:
> On Sun, Oct 20, 2024 at 10:13=E2=80=AFAM Tom Lane <tgl@sss.pgh.pa.us> wr=
ote:
>> But it seems like we could get an easy win by adjusting
>> plpgsql_exec_function along the lines of
>> ...

> I tried this change and couldn't get it to work, on the next line:
>     if (VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(var->value)))
> var->value might not be a pointer, as it seems at least from my gdb
> scratching, but say an integer.  This segfaults on non-array but
> non-expandable datum.

Oh, duh --- the typisarray test serves to eliminate pass-by-value
types.  We need the same test that exec_assign_value makes,
!var->datatype->typbyval, before it's safe to apply DatumGetPointer.
So line 549 needs to be more like

-                    if (!var->isnull && var->datatype->typisarray)
+                    if (!var->isnull && !var->datatype->typbyval)

> Another comment that caught my eye was this one:
> https://github.com/postgres/postgres/blob/master/src/pl/plpgsql/src/pl_e=
xec.c#L8304
> Not sure what the implication is there.

Yeah, that's some more unfinished business.  I'm not sure if it
matters to your use-case or not.

BTW, we probably should move this thread to pgsql-hackers.

			regards, tom lane