
> > > How about: use overwriting smgr + put old records into rollback
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > > segments - RS - (you have to keep them somewhere till TX's running
> > > anyway) + use WAL only as REDO log (RS will be used to 
> rollback TX'
> > > changes and WAL will be used for RS/data files recovery).
> > > Something like what Oracle does.
> > 
> > We have all the info we need in WAL and in the old rows,
> > why would you want to write them to RS ?
> > You only need RS for overwriting smgr.
> 
> This is what I'm saying - implement Overwriting smgr...

Yes I am sorry, I am catching up on email and had not read Bruce's 
comment (nor yours correctly) :-(

I was also long in the pro overwriting camp, because I am used to 
non MVCC dbs like DB/2 and Informix. (which I like very much) 
But I am starting to doubt that overwriting is really so good for
an MVCC db. And I don't think PG wants to switch to non MVCC :-)

Imho it would only need a much more aggressive VACUUM backend.
(aka garbage collector :-) Maybe It could be designed to sniff the 
redo log (buffer) to get a hint at what to actually clean out next.

Andreas

Fri, 25 Jan 2002 22:51:24 +0100
"Zeugswetter Andreas SB SD" <ZeugswetterA@spardat.at>
Re: Savepoints