From: Richard Huxton <dev@archonet.com>
To: Michal Taborsky <michal.taborsky@mall.cz>
Cc: pgsql-performance@postgresql.org
Subject: Re: Searching union views not using indices
Date: Fri, 04 Nov 2005 15:01:05 +0000
Message-ID: <436B77B1.7090602@archonet.com> (raw)
In-Reply-To: <436B4836.7030300@mall.cz>
References: <436B4836.7030300@mall.cz>
Michal Taborsky wrote:
...
> UNION
...
> The result is sequential scan on all tables, append, sort and then
> filter scan on this whole thing. Which of course is slow as hell. We use
> version 8.0.2.
>
> And now the question: Is there a way to force the planner to push the
> condition lower, so it will use the index? Or do you use some tricks in
> this scenario? Thanks for your suggestions.
Try "UNION ALL", since UNION is defined as removing duplicates, which
probably accounts for the sort.
--
Richard Huxton
Archonet Ltd
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To: pgsql-performance@postgresql.org
Cc: dev@archonet.com, michal.taborsky@mall.cz
Subject: Re: Searching union views not using indices
In-Reply-To: <436B77B1.7090602@archonet.com>
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