Re: PITR, checkpoint, and local relations

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

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>, PostgreSQL Hacker <pgsql-hackers@postgresql.org>
Date: 2002-08-02T20:01:40Z
Lists: pgsql-hackers
"J. R. Nield" <jrnield@usol.com> writes:
> The predicate for files we MUST (fuzzy) copy is: 
>   File exists at start of backup && File exists at end of backup

Right, which seems to me to negate all these claims about needing a
(horribly messy) way to read uncommitted system catalog entries, do
blind reads, etc.  What's wrong with just exec'ing tar after having
done a checkpoint?

(In particular, I *strongly* object to using the buffer manager at all
for reading files for backup.  That's pretty much guaranteed to blow out
buffer cache.  Use plain OS-level file reads.  An OS directory search
will do fine for finding what you need to read, too.)

			regards, tom lane