Re: UNION ALL and sequential scans

From: Tom Lane
Subject: Re: UNION ALL and sequential scans
Date: ,
Msg-id: 12329.1242314433@sss.pgh.pa.us
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In response to: Re: UNION ALL and sequential scans  (Mathieu De Zutter)
List: pgsql-performance

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UNION ALL and sequential scans  ("Brad Jorsch", )
 Re: UNION ALL and sequential scans  (Tom Lane, )
  Re: UNION ALL and sequential scans  (Mathieu De Zutter, )
   Re: UNION ALL and sequential scans  (Tom Lane, )

Mathieu De Zutter <> writes:
> On Thu, May 14, 2009 at 4:52 PM, Tom Lane <> wrote:
>> It's an ancient and fundamental limitation that is fixed in 8.4.
>> Do not expect to see it fixed in 8.3.x.

> Does this also apply to the case of a join on an inherited table ?

> example: http://archives.postgresql.org/pgsql-performance/2003-10/msg00018.php

Well, the particular issue described in that message is long gone.
What Brad is complaining about is non-strict expressions in the
outputs of append-relation members.  An inheritance tree also forms
an append-relation, but AFAIK there is no way to have anything but
simple Vars in its outputs so the case wouldn't arise.  Do you have
a specific problem example in mind?

            regards, tom lane


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