Re: PITR: XLog File compression on Archive

On Tue, Aug 24, 2004 at 12:05:33AM +0200, Gaetano Mendola wrote:
> Simon Riggs wrote:
> 
> >As a result, I have thought that there may be a way to remove those pages
> >from the xlog files immediately before being copied away to archive, 
> >without effecting crash recovery logic AT ALL.
> 
> So this means that the way to have an "hot spare" postgres that play
> the logs while are arriving is not applicable anymore ?

No, it doesn't.  Your scheme can still work; it will just have less work
to do.

Basically the point here is skipping the restoration of whole pages.  In
a non-crashed scenario there's no need to restore them, because it is
only used if the system happenned to crash while there was a write in
progress.  Supposedly this cannot happen on your hot-spare system.

-- 
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"La persona que no quería pecar / estaba obligada a sentarse
en duras y empinadas sillas    / desprovistas, por cierto
de blandos atenuantes"                          (Patricio Vogel)