Re: join over 12 tables takes 3 secs to plan - Mailing list pgsql-performance

From Hilmar Lapp
Subject Re: join over 12 tables takes 3 secs to plan
Date
Msg-id B3DCB6D1-1E95-11D7-9244-000393B4BFF6@gmx.net
Whole thread Raw
In response to Re: join over 12 tables takes 3 secs to plan  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: join over 12 tables takes 3 secs to plan
Re: join over 12 tables takes 3 secs to plan
List pgsql-performance
Thanks for the pointer Tom. The application that's generating those
queries is open source, so I could even go in and hack the query
generating code accordingly, but I doubt I can spare that time. Given
the information in the document you pointed me at and Neil's email I
assume there is no other immediate remedy.

As an added note, appreciating that query optimization is a difficult
problem, and I do think PostgreSQL is a great product. Having said
that, I've written 16-table joins for Oracle and always found them to
plan within a second or two, so that's why I thought there's nothing
special about the query I posted ... I'm not saying this to be bashful
about PostgreSQL, but rather to suggest that apparently there are ways
to do it pretty fast.

I'm only starting to use PostgreSQL and making experiences, so I'm
asking for forgiveness what may occasionally seem to be ignorant ...

    -hilmar

On Thursday, January 2, 2003, at 12:24  PM, Tom Lane wrote:

> Hilmar Lapp <hlapp@gmx.net> writes:
>> I have a query generated by an application (not mine, but there's
>> nothing I can find that looks bad about the query itself) that takes
>> an
>> excessive amount of time to return even though there are almost no
>> rows
>> in the schema yet.
>
> Read
> http://www.ca.postgresql.org/users-lounge/docs/7.3/postgres/explicit-
> joins.html
>
>             regards, tom lane
>
>
--
-------------------------------------------------------------
Hilmar Lapp                            email: lapp at gnf.org
GNF, San Diego, Ca. 92121              phone: +1-858-812-1757
-------------------------------------------------------------


pgsql-performance by date:

Previous
From: "Steve Wolfe"
Date:
Subject: Re: Question on hardware & server capacity
Next
From: Hilmar Lapp
Date:
Subject: Re: join over 12 tables takes 3 secs to plan