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Re: slow information schema with thausand users, seq.scan pg_authid

From: Andrew - Supernews <andrew+nonews(at)supernews(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: slow information schema with thausand users, seq.scan pg_authid
Date: 2006-02-06 14:13:21
Message-ID: slrnduemc1.2k35.andrew+nonews@atlantis.supernews.net (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-patches
On 2006-02-06, Peter Eisentraut <peter_e(at)gmx(dot)net> wrote:
> I suggest that your problem is the join order (unless you have 500000 
> tables as well).  Moreover, using left joins instead of inner joins 
> seems to be quite useless unless you plan to have tables that are not 
> owned by anyone and are not in a schema.

Perhaps you missed the fact that the query was not one that he wrote,
but is the query that psql uses for \ds ?

>> there is any possibility creating index for pg_authid?
>
> It already has indexes.

True, but they're not being used where you'd expect. This seems to be
something to do with the fact that it's not pg_authid which is being
accessed, but rather the view pg_roles.

-- 
Andrew, Supernews
http://www.supernews.com - individual and corporate NNTP services

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