Re: pg_class has no toast table?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Simon Riggs <simon(at)2ndQuadrant(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: pg_class has no toast table?
Date: 2010-02-07 17:15:49
Message-ID: 24753.1265562949@sss.pgh.pa.us
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Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
> On Sat, 2010-02-06 at 13:04 -0500, Tom Lane wrote:
>> We might still want to consider toast-ifying pg_class if anyone ever
>> complains about not having room for wide relacl values; but CLUSTER
>> shouldn't be a forcing function for such decisions.

> What failure do you get if you have too many relacls or too many
> reloptions? We would want it to fail cleanly. Is it enough to mark those
> columns as MAIN storage?

You'd get a "tuple too large" error if the tuple still didn't fit on a
page after compressing the wide columns. We don't need to do anything
special for that.

> Neither of those is worth worrying about a toast table for. Anybody with
> that long a relacl hasn't thought about their admin structure enough.

Yeah, that's my thought also. You'd likely start having performance
problems with thousand-item ACL lists anyway. You should switch over to
using groups long before that.

regards, tom lane

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