RE: Another little xlog change idea

From: "Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM>
To: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: RE: Another little xlog change idea
Date: 2001-03-13 18:25:41
Message-ID: 8F4C99C66D04D4118F580090272A7A234D331A@sectorbase1.sectorbase.com
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> As long as I'm about to change the xlog page headers, I have another
> little idea. Wouldn't it be a good idea to allow three backup pages
> per xlog record, not only two? It seems like three pages would be
> a natural requirement for logging operations like index page splits.

On index splits we don't backup left and right whole pages - just part
of pages filled by index tuples. This saves us ~ 8K for indices with
small keys.

> We could support as many as four pages per record, but that would mean
> having no free global bits in the info byte, which might be a
> bad idea. I think three page bits and one free bit is a good compromise.
> Thoughts?

You almost forget that we are in beta and should fix bugs, not implement
features which useless in current version -:) Add comments and that will
be enough, no?

Vadim

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