Re: Pushing IN (subquery) down through UNION ALL?

From: Thom Brown <thom(at)linux(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Dave Johansen <davejohansen(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Pushing IN (subquery) down through UNION ALL?
Date: 2011-03-02 14:11:51
Message-ID: AANLkTi=wpyTgrHa63-OdpFFpaEr=82N9ijJH0kXTwRBK@mail.gmail.com
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On 2 March 2011 19:38, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Thu, Feb 24, 2011 at 11:38 AM, Dave Johansen <davejohansen(at)gmail(dot)com> wrote:
>> I also just noticed that an ORDER BY x LIMIT n optimization is not pushed
>> down through the UNION ALL as well. I understand that this may be a little
>> trickier because the ORDER BY and LIMIT would need to be applied to the
>> subqueries and then re-applied after the APPEND,
>
> PostgreSQL 9.1 will know how to do this, FWIW.

Out of curiosity, what was the commit for this?

--
Thom Brown
Twitter: @darkixion
IRC (freenode): dark_ixion
Registered Linux user: #516935

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