From: | "J(dot) R(dot) Nield" <jrnield(at)usol(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Richard Tucker <richt(at)multera(dot)com>, Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, PostgreSQL Hacker <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: PITR, checkpoint, and local relations |
Date: | 2002-08-02 20:45:10 |
Message-ID: | 1028321114.1264.4.camel@localhost.localdomain |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Fri, 2002-08-02 at 16:01, Tom Lane wrote:
> "J. R. Nield" <jrnield(at)usol(dot)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?
>
There is no need to read uncommitted system catalog entries. Just take a
snapshot of the directory to get the OID's. You don't care whether the
get deleted before you get to them, because the log will take care of
that.
> (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.)
How do you get atomic block copies otherwise?
>
> regards, tom lane
>
--
J. R. Nield
jrnield(at)usol(dot)com
From | Date | Subject | |
---|---|---|---|
Next Message | Mikheev, Vadim | 2002-08-02 20:55:19 | Re: PITR, checkpoint, and local relations |
Previous Message | Tom Lane | 2002-08-02 20:25:06 | Re: getpid() function |