Re: How does the planner execute unions?

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: Chris Hoover <revoohc(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: How does the planner execute unions?
Date: 2005-08-26 20:45:54
Message-ID: 20050826204554.GB11078@wolff.to
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On Fri, Aug 26, 2005 at 16:14:18 -0400,
Chris Hoover <revoohc(at)gmail(dot)com> wrote:
> Hopefully a quick question.
>
> In 7.3.4, how does the planner execute a query with union alls in it?
>
> Does it execute the unions serially, or does it launch a "thread" for
> each union (or maybe something else entirely).

Postgres doesn't have parallel execution of parts of queries. So it is
going to do one part followed by the other part.

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