Re: proposal: schema variables

Hi

st 4. 3. 2026 v 11:03 odesílatel Haritabh Gupta <haritabh1992(at)gmail(dot)com>
napsal:

> Hi,
>
> While reviewing I came across this behaviour and wanted to
> check whether it's intended:
>
> CREATE TEMP VARIABLE y AS int;
> LET y = 42;
>
> BEGIN;
> SAVEPOINT s1;
> LET y = generate_series(1,2); -- ERROR: too many rows
> ROLLBACK TO s1;
> SELECT VARIABLE(y); -- returns 1, not 42
>
> It looks like svariableReceiveSlot writes the first row to the
> variable (pfree'ing the old datum) before the second row triggers the
> error, so the old value is lost even though LET failed.
>
> I understand variable values are intentionally non-transactional, but
> is it expected that a failed LET has this side effect?
>

Yes, it does like you describe it. It is the most simple solution, because
I don't need any extra buffer, and I can assign the value immediately when
I have the value.

I think I can postpone an assignment to svariableShutdownReceiver with a
few more lines to get the behaviour that you expect.

Regards

Pavel

> ---
> Haritabh Gupta
> Supabase