Re: Reduction in WAL for UPDATEs

From: "Zeugswetter Andreas ADI SD" <ZeugswetterA(at)spardat(dot)at>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Gregory Stark" <stark(at)enterprisedb(dot)com>
Cc: "Kenneth Marshall" <ktm(at)rice(dot)edu>, <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: Reduction in WAL for UPDATEs
Date: 2007-03-28 16:20:02
Message-ID: E1539E0ED7043848906A8FF995BDA57901E7B00A@m0143.s-mxs.net
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> > I agree that these values need a second look. I think a
> > TOAST_TUPLE_THRESHOLD well smaller than the current value would
still
> > easily pay its way. With a little caution to avoid wasting too much
> > effort on the last few bytes I suspect even as low as
> 400-500 bytes is probably worthwhile.

But a seq scan (or non cached access) would suddenly mutate to multiple
random accesses, so this is not a win-win situation.

Btw: Do we consider the existance of toasted columns in the seq-scan
cost estimation ?

Andreas

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