> > The reason you have to visit the main table is that tuple validity
> > status is only stored in the main table, not in each index. 
> > See prior discussions in the archives.
> 
> But how Oracle handles this?

Oracle doesn't have non-overwriting storage manager but uses
rollback segments to maintain MVCC. Rollback segments are used
to restore valid version of entire index/table page.

Vadim

Tue, 23 Jan 2001 10:23:22 -0800
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM>
RE: Does Oracle store values in indices?
> > > The reason you have to visit the main table is that tuple validity
> > > status is only stored in the main table, not in each index.
> > > See prior discussions in the archives.
> >
> > But how Oracle handles this?
>
> Oracle doesn't have non-overwriting storage manager but uses
> rollback segments to maintain MVCC. Rollback segments are used
> to restore valid version of entire index/table page.

Are there any plans to have something like this? I mean overwriting storage 
manager.

-- 
Sincerely Yours,
Denis Perchine

----------------------------------
E-Mail: dyp@perchine.com
HomePage: http://www.perchine.com/dyp/
FidoNet: 2:5000/120.5
----------------------------------

Wed, 24 Jan 2001 00:25:53 +0600
Denis Perchine <dyp@perchine.com>
Re: Does Oracle store values in indices?
[ Charset KOI8-R unsupported, converting... ]
> > > > The reason you have to visit the main table is that tuple validity
> > > > status is only stored in the main table, not in each index.
> > > > See prior discussions in the archives.
> > >
> > > But how Oracle handles this?
> >
> > Oracle doesn't have non-overwriting storage manager but uses
> > rollback segments to maintain MVCC. Rollback segments are used
> > to restore valid version of entire index/table page.
> 
> Are there any plans to have something like this? I mean overwriting storage 
> manager.

We hope to have it some day, hopefully soon.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Tue, 23 Jan 2001 14:02:23 -0500 (EST)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: Does Oracle store values in indices?
* Bruce Momjian <pgman@candle.pha.pa.us> [010123 11:17] wrote:
> [ Charset KOI8-R unsupported, converting... ]
> > > > > The reason you have to visit the main table is that tuple validity
> > > > > status is only stored in the main table, not in each index.
> > > > > See prior discussions in the archives.
> > > >
> > > > But how Oracle handles this?
> > >
> > > Oracle doesn't have non-overwriting storage manager but uses
> > > rollback segments to maintain MVCC. Rollback segments are used
> > > to restore valid version of entire index/table page.
> > 
> > Are there any plans to have something like this? I mean overwriting storage 
> > manager.
> 
> We hope to have it some day, hopefully soon.

Vadim says that he hopes it to be done by 7.2, so if things go
well it shouldn't be that far off...

-- 
-Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org]
"I have the heart of a child; I keep it in a jar on my desk."

Tue, 23 Jan 2001 11:38:29 -0800
Alfred Perlstein <bright@wintelcom.net>
Re: Does Oracle store values in indices?