Re: pl/python do not delete function arguments

Jan Urbański <wulczer@wulczer.org>

From: Jan Urbański <wulczer@wulczer.org>
To: Peter Eisentraut <peter_e@gmx.net>
Cc: Hitoshi Harada <umi.tanuki@gmail.com>, Postgres - Hackers <pgsql-hackers@postgresql.org>
Date: 2011-02-15T08:58:15Z
Lists: pgsql-hackers
----- Original message -----
> On mån, 2011-02-14 at 22:22 +0100, Jan Urbański wrote:
> > The problem is that every *second* call to the function fails,
> > regardless of the number. The first execution succeeds, but then
> > PLy_delete_args deletes the argument from the globals, and when the
> > next execution tries to fetch "n" from it, it raises a KeyError.
> 
> This isn't quite right either, because it obviously depends on the
> recursion somehow.   So in
> 
> SELECT recursion_test(5);
> SELECT recursion_test(4);
> 
> it is the first recursive invocation of the (4) call that fails.   If you
> just do
> 
> SELECT recursion_test(1);
> SELECT recursion_test(1);
> SELECT recursion_test(1);
> 
> nothing fails.   (We'd have noticed that sooner, obviously. ;-) )

Isn't that because with 1 there is no recursion, i.e. plpy.execute never gets called from Python?

> But in
> 
> SELECT recursion_test(1);
> SELECT recursion_test(4);
> SELECT recursion_test(1);
> 
> it's the last (1) call, which is not recursive, that fails.

Because the invocation that actually recurses sets up the scene for failure.

Jan