> > But needed if we want to get rid of vacuum and have savepoints.
> 
> Hmm. How do you implement savepoints ? When there is rollback 
> to savepoint do you use xlog to undo all changes which the particular 
> transaction has done ? Hmmm it seems nice ... these resords are locked by 
> such transaction so that it can safely undo them :-)
> Am I right ?

Yes, but there is no savepoints in 7.1 - hopefully in 7.2

> But how can you use xlog to get rid of vacuum ? Do you treat 
> all delete log records as candidates for free space ?

Vaccum removes deleted records *and* records inserted by aborted
transactions - last ones will be removed by UNDO.

Vadim

Fri, 9 Mar 2001 12:11:36 -0800 
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM>
RE: WAL & SHM principles