Re: BUG #17669: Invalid TOAST pointer in PL/pgSQL variable

PG Bug reporting form <noreply@postgresql.org> writes:
> create function f() returns text as $$
> declare
>   s text;
> begin
>   select b into s from t where a = 1;
>   truncate t;
>   return s;
> end;
> $$ language plpgsql;

> postgres=# select f();
> ERROR:  missing chunk number 0 for toast value 24727 in pg_toast_24722

To prevent that, every fetch into a plpgsql variable would have
to immediately detoast the value, in case somebody did something
as weird as dropping/truncating the table later in the function.
That's an awfully expensive bit of protection.  We do in fact
do it like that in procedures (more specifically, in non-atomic
contexts), so a possible workaround for you is to make this a
procedure not a function.  I'm disinclined to change it otherwise.

            regards, tom lane