Re: Modifying TOAST thresholds

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Simon Riggs" <simon(at)2ndquadrant(dot)com>
Cc: "Gregory Stark" <stark(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Modifying TOAST thresholds
Date: 2007-03-29 16:05:49
Message-ID: 23147.1175184349@sss.pgh.pa.us
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"Simon Riggs" <simon(at)2ndquadrant(dot)com> writes:
> Well it certainly seems worth separating them. It does seem possible
> that recursive toasting effected some of the earlier results we looked
> at.

> Would you like me to do this, or will you?

I'm willing to do the code changes to separate TOAST_THRESHOLD from
the toast chunk size, but I do not have the time or facilities to do
any performance testing for different parameter choices. Anyone want
to work on that?

> I'd like to get some mechanism for reducing WAL volume into 8.3, whether
> its configurable toast or WAL reduction for UPDATEs. If for no other
> reason than making backup and availability solutions more manageable.

I think the WAL-reduction proposal needs more time and thought than is
feasible before 8.3. OTOH, tuning the TOAST parameters seems like
something we understand well enough already, we just need to put some
cycles into testing different alternatives. I would have no objection
to someone working on that during April and delivering a final patch
sometime before beta.

regards, tom lane

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