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

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

From
Tom Lane
Date:
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(-)


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

From
David Fetter
Date:
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.
--
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Re: pgsql: Fix another join removal bug: the check on PlaceHolderVars was w

From
Tom Lane
Date:
David Fetter <david@fetter.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

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

From
Andres Freund
Date:
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