Re: bug (?) with RULEs with WHERE

From: Kovacs Zoltan <kovacsz(at)pc10(dot)radnoti-szeged(dot)sulinet(dot)hu>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: bug (?) with RULEs with WHERE
Date: 2001-10-30 12:57:57
Message-ID: Pine.LNX.4.21.0110301346020.11253-100000@pc10.radnoti-szeged.sulinet.hu
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Sat, 27 Oct 2001, Tom Lane wrote:

> Kovacs Zoltan <kovacsz(at)pc10(dot)radnoti-szeged(dot)sulinet(dot)hu> writes:
> > [...]
> > foo=# CREATE RULE d AS ON INSERT TO c WHERE new.foo=5 DO INSTEAD SELECT foo FROM b;
> > CREATE
> > foo=# INSERT INTO c VALUES (5);
> > ERROR: Cannot insert into a view without an appropriate rule
>
> You didn't provide a rule covering the new.foo<>5 case.
>
> In practice, you *must* have an unconditional INSTEAD rule present for
> any view operation you want to allow. It can be DO INSTEAD NOTHING,
> and then you can do all your useful work in conditional rules, but the
> unconditional rule must be there. Else the system thinks that perhaps
> the insert into the view would really happen.

Thank you, I see. It works now. But in 7.1.1 on a rather complex view I
experienced that the RULE has been executed as many times as many rows the
view contains, although I added a WHERE to filter the rows: in fact it
should have been executed only once. In 7.1.3 this problem doesn't
occur. Has anything been changed since 7.1.1 in this code?

So I'm migrating to 7.1.3 now. But currently I'm still having problems
with user authentication (I get "Password authentication failed for user
'xxxx'." errors). I always used

INSERT INTO pg_shadow...

Is this changed? With

ALTER USER...

it works, of course. Do you suggest stopping use "INSERT INTO
pg_shadow..."?

TIA, Zoltan

Kov\'acs, Zolt\'an
kovacsz(at)pc10(dot)radnoti-szeged(dot)sulinet(dot)hu
http://www.math.u-szeged.hu/~kovzol
ftp://pc10.radnoti-szeged.sulinet.hu/home/kovacsz

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Thomas Lockhart 2001-10-30 13:24:26 Re: pgsql-committers?
Previous Message Tille, Andreas 2001-10-30 12:46:22 Re: Serious performance problem