Re: Optimizer generates bad plans. - Mailing list pgsql-hackers

From Kris Jurka
Subject Re: Optimizer generates bad plans.
Date
Msg-id Pine.LNX.4.33.0209191826370.15929-100000@leary.csoft.net
Whole thread Raw
In response to Re: Optimizer generates bad plans.  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: Optimizer generates bad plans.
List pgsql-hackers
Well I was really hoping pg_constraint would solve all my problems, but
since contrib/array is not installed by default the conkeys and confkeys
columns aren't terribly useful because they can't be joined to
pg_attribute.

Also there is not a column to tell you the unique constraint that
supports a given foreign key constraint.

See my post to bugs:

http://fts.postgresql.org/db/mw/msg.html?mid=1074855

Kris Jurka


On Thu, 19 Sep 2002, Bruce Momjian wrote:

>
> Congratulations.  That is the largest plan I have ever seen.  ;-)
>
> ---------------------------------------------------------------------------
>
> Kris Jurka wrote:
> > While adding schema support to the JDBC Driver, I came across a query
> > which occasionally generates some spectacularly bad plans.  I have
> > attached the query and explain analyze outputs against today's cvs head
> > for queries that take between 9 and 845941 msec.  In the JDBC Driver I
> > will specify a reasonable join order using explicit JOINs, but I thought
> > someone might be interested in a test case for the optimizer.
>
> --
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman@candle.pha.pa.us               |  (610) 359-1001
>   +  If your life is a hard drive,     |  13 Roberts Road
>   +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
>
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