From: Bruno Wolff III <bruno@wolff.to>
To: Chris Hoover <revoohc@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: How does the planner execute unions?
Date: Fri, 26 Aug 2005 15:45:54 -0500
Message-ID: <20050826204554.GB11078@wolff.to> (raw)
In-Reply-To: <1d219a6f0508261314516fdb0@mail.gmail.com>
References: <1d219a6f0508261314516fdb0@mail.gmail.com>
On Fri, Aug 26, 2005 at 16:14:18 -0400,
Chris Hoover <revoohc@gmail.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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To: pgsql-performance@postgresql.org
Cc: bruno@wolff.to, revoohc@gmail.com
Subject: Re: How does the planner execute unions?
In-Reply-To: <20050826204554.GB11078@wolff.to>
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