Re: PITR logging control program - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: PITR logging control program
Date
Msg-id 20040429141113.GG2258@dcc.uchile.cl
Whole thread Raw
In response to Re: PITR logging control program  (Alvaro Herrera <alvherre@dcc.uchile.cl>)
Responses Re: PITR logging control program  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
On Thu, Apr 29, 2004 at 10:07:01AM -0400, Bruce Momjian wrote:
> Alvaro Herrera wrote:

> > Is the API able to indicate a written but not-yet-filled WAL segment?
> > So an archiver could copy the filled part, and refill it later.  This
> > may be needed because a segment could take a while to be filled.
> 
> I couldn't figure that out, but I don't think it does.  It would have to
> lock the WAL writes so it could get a good copy, I think, and I didn't
> see that.

I'm not sure but I don't think so.  You don't have to lock the WAL for
writing, because it will always write later in the file than you are
allowed to read.  (If you read more than you were told to, it's your
fault as an archiver.)

-- 
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"Et put se mouve" (Galileo Galilei)


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