Horton

Re: [PATCHES] Full page writes improvement, code update

Zeugswetter Andreas DCP SD <zeugswettera@spardat.at>

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From: "Zeugswetter Andreas ADI SD" <ZeugswetterA@spardat.at>
To: "Koichi Suzuki" <suzuki.koichi@oss.ntt.co.jp>, "Simon Riggs" <simon@2ndquadrant.com>
Cc: <josh@agliodbs.com>, <pgsql-hackers@postgresql.org>, <pgsql-patches@postgresql.org>
Date: 2007-03-30T08:22:23Z
Lists: pgsql-hackers 
> Without a switch, because both full page writes and 
> corresponding logical log is included in WAL, this will 
> increase WAL size slightly 
> (maybe about five percent or so).   If everybody is happy 
> with this, we 
> don't need a switch.

Sorry, I still don't understand that. What is the "corresponding logical
log" ?
It seems to me, that a full page WAL record has enough info to produce a

dummy LSN WAL entry. So insead of just cutting the full page wal record
you 
could replace it with a LSN WAL entry when archiving the log.

Then all that is needed is the one flag, no extra space ?

Andreas