Re: AW: [HACKERS] Re: PL/PgSQL discussion

Andreas Zeugswetter wrote:
>
> >From my experience, it *** is *** impossible. I would be glad if somebody
> told me different, but to my understanding the doc is wrong here.
>
> Andreas
>
> >> Currently only 'null' and 'single value'. The executor
> >> doesn't accept anything else for non-sql language functions.
> >> PL functions are treated by the executor like 'C' functions.
> >
> >Actually what I understood from the docs was thatit is 'terribly complicated' and 'beyond the
> >scope of this tutorial', but not impossible ;)

I have been thinking about that quite a time and when David
Gould said 'looks like PL functions want to _be_ SQL
functions', my first action was scratching my head. Then I
thought it would blow up the parser and executor with things
they wheren't designed for and dropped these thoughts.

Anyway - thanks David - it was a push into the right
direction. Not that I think PL functions should become real
SQL functions processed by the backends main parser and
executor. But they might become something between 'C' and
'SQL'.

The executor could check in ExecMakeFunctionResult() that the
function is a PL function (simply by looking at
fcache->func.fn_plhandler). So it is possible that the
Executor treats PL functions somewhat like
postquel_function().

My PL/pgSQL is now at the state, that I can write functions.
I'll leave triggers for later and take a look if that all is
possible. Would be really nice to enable tuples and sets of
tuples as PL return types and finally beeing able to do a

DECLARE ret EMP%ROWTYPE;
BEGIN
...
FOR ret IN SELECT ... LOOP
RETURN ret AND RESUME;
ENDLOOP;
...
END;

from PL/pgSQL. Well, returning and resume later might cause
some trouble with SPI, but let's see.

Jan

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