Oracle-L: RE: Automatic Segment Space Management

From: K Gopalakrishnan <kaygopal_at_yahoo.com>
Date: Thu, 20 Feb 2003 03:10:04 -0800
Message-ID: <F001.00552A55.20030220031004@fatcity.com>

Kirti:

I have not complely following this thread. But I am sure it is worth mentioning even if someone already mentioned also. In ASSM there would be two highwatermarks called low high water mark and high high water mark.

The high high water mark is the actual high water mark (like in the Freelist Managed Segments) and the low high water mark is the new one which is introduced in ASSM. i.e till low HWM all blocks are completely used and from LHWM to HWHM there could be some blocks unused. During sequential scan it has to read till HHWM (i.e it should scan empty block also).

But I think by scanning the L2 bitmaps the process can find the unused blocks and skip that during sequential scanning, though I have not tested it thoroughly.

Best Regards,
K Gopalakrishnan
Bangalore, INDIA (Now in Austria)

"Deshpande, Kirti" <kirti.deshpande_at_verizon.com> wrote:
> In a very limited tests that I performed with ASSM (quite some time
> ago), I found that it tends to use a bit more space than non-ASSM.
> Something to keep in mind when FTS is used to access tables.
> Not sure if this changed in 9.2.0.2.x.
>
> - Kirti
>

Have a nice day !!

Best Regards,
K Gopalakrishnan,
Bangalore, INDIA.

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: K Gopalakrishnan
  INET: kaygopal_at_yahoo.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).

Received on Thu Feb 20 2003 - 05:10:04 CST