Kirti:
There are some (or more) errors in my previous post. The process can
not find the partly filled/free blocks until it scans the L1 bitmaps
(I said L2 bitmap in the previous post as I was in half-sleep while
composting the message) and the L2 bitmaps just point the scanning
process to the respective L1 bitmaps.
And the other overhead in ASSM is, there are chances you will waste
around 1-5% (depending on the block size,etc) blocks for just keeping
the meta data and this could be a overhead along with the space waster
in between the Low HWN and high HWM.
Best Regards
K Gopalakrishnan
- K Gopalakrishnan <kaygopal_at_yahoo.com> wrote:
> 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
>
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Have a nice day !!
Best Regards,
K Gopalakrishnan,
Bangalore, INDIA.
--
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--
Author: K Gopalakrishnan
INET: kaygopal_at_yahoo.com
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Received on Thu Feb 20 2003 - 05:44:10 CST
