Re: pgsql: Fix another join removal bug: the check on PlaceHolderVars was w

Lists: pgsql-committers
From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: pgsql-committers(at)postgresql(dot)org
Subject: pgsql: Fix another join removal bug: the check on PlaceHolderVars was w
Date: 2010-09-25 23:04:28
Message-ID: E1OzdnA-0004nC-N9@gemulon.postgresql.org
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Fix another join removal bug: the check on PlaceHolderVars was wrong.

The previous coding would decide that join removal was unsafe upon finding
a PlaceHolderVar that needed to be evaluated at the inner rel and then used
above the join. However, this fails to cover the case of PlaceHolderVars
that refer to both the inner rel and some other rels. Per bug report from
Andrus.

Branch
------
REL9_0_STABLE

Details
-------
http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=7fc8db849106db91e1053ed25045eb4fa877f212

Modified Files
--------------
src/backend/optimizer/plan/analyzejoins.c | 18 +++++++++++++-----
src/test/regress/expected/join.out | 21 +++++++++++++++++++++
src/test/regress/sql/join.sql | 15 +++++++++++++++
3 files changed, 49 insertions(+), 5 deletions(-)

From: David Fetter <david(at)fetter(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-committers(at)postgresql(dot)org
Subject: Re: pgsql: Fix another join removal bug: the check on PlaceHolderVars was w
Date: 2010-09-26 00:29:16
Message-ID: 20100926002916.GA22240@fetter.org
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On Sat, Sep 25, 2010 at 11:04:28PM +0000, Tom Lane wrote:
> Fix another join removal bug: the check on PlaceHolderVars was
> wrong.
>
> The previous coding would decide that join removal was unsafe upon
> finding a PlaceHolderVar that needed to be evaluated at the inner
> rel and then used above the join. However, this fails to cover the
> case of PlaceHolderVars that refer to both the inner rel and some
> other rels. Per bug report from Andrus.

The person who found it originally was Kirill (xitology) Simonov. He
brought it up in IRC. :)

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
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From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: David Fetter <david(at)fetter(dot)org>
Cc: pgsql-committers(at)postgresql(dot)org
Subject: Re: pgsql: Fix another join removal bug: the check on PlaceHolderVars was w
Date: 2010-09-26 00:52:39
Message-ID: 17499.1285462359@sss.pgh.pa.us
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David Fetter <david(at)fetter(dot)org> writes:
> On Sat, Sep 25, 2010 at 11:04:28PM +0000, Tom Lane wrote:
>> The previous coding would decide that join removal was unsafe upon
>> finding a PlaceHolderVar that needed to be evaluated at the inner
>> rel and then used above the join. However, this fails to cover the
>> case of PlaceHolderVars that refer to both the inner rel and some
>> other rels. Per bug report from Andrus.

> The person who found it originally was Kirill (xitology) Simonov. He
> brought it up in IRC. :)

[ shrug ... ] I can only go by what I see in the bug report.

regards, tom lane

From: Andres Freund <andres(at)anarazel(dot)de>
To: pgsql-committers(at)postgresql(dot)org
Cc: David Fetter <david(at)fetter(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: pgsql: Fix another join removal bug: the check on PlaceHolderVars was w
Date: 2010-09-26 10:36:47
Message-ID: 201009261236.48805.andres@anarazel.de
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On Sunday 26 September 2010 02:29:16 David Fetter wrote:
> On Sat, Sep 25, 2010 at 11:04:28PM +0000, Tom Lane wrote:
> > Fix another join removal bug: the check on PlaceHolderVars was
> > wrong.
> >
> > The previous coding would decide that join removal was unsafe upon
> > finding a PlaceHolderVar that needed to be evaluated at the inner
> > rel and then used above the join. However, this fails to cover the
> > case of PlaceHolderVars that refer to both the inner rel and some
> > other rels. Per bug report from Andrus.
>
> The person who found it originally was Kirill (xitology) Simonov. He
> brought it up in IRC. :)
No, thats a different bug... For one its affecting 8.4 at least as well, for
another its not yet fixed ;-)

Andres