Horton

Re: PITR, checkpoint, and local relations

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: "J. R. Nield" <jrnield@usol.com>
Cc: Richard Tucker <richt@multera.com>, Bruce Momjian <pgman@candle.pha.pa.us>, Christopher Kings-Lynne <chriskl@familyhealth.com.au>, PostgreSQL Hacker <pgsql-hackers@postgresql.org>
Date: 2002-08-08T03:41:17Z
Lists: pgsql-hackers 
"J. R. Nield" <jrnield@usol.com> writes:
> The xlog code must allow us to force an advance to the next log file,
> and truncate the archived file when it's copied so as not to waste
> space.

Uh, why?  Why not just force a checkpoint and remember the exact
location of the checkpoint within the current log file?

When and if you roll back to a prior checkpoint, you'd want to start the
system running forward with a new xlog file, I think (compare what
pg_resetxlog does).  But it doesn't follow that you MUST force an xlog
file boundary simply because you're taking a backup.

> This complicates both the recovery logic and XLogInsert, and I'm trying
> to kill the "last" latent bug in that feature now.

Indeed.  How about keeping it simple, instead?

			regards, tom lane