Re: Initial,Next Extents and Byte allocation confusion

From: Mark Landa <mlanda_at_earthlink.net>
Date: 1998/02/08
Message-ID: <34DDBEF6.4998F033@earthlink.net>#1/1

There is also some overhead incurred
in each database block for header data.

M.Landa

Joel Garry wrote:

> In article <34DB898E.3EBE_at_sabre.com>,
> Poorna Prakash <poorna_prakash_at_sabre.com> wrote:
> >Please clarify the confusion I have on extent allocation
> >and the bytes allocated. Upon inquiring the USER_INDEXES & USER_SEGMENTS
> >data dictionary view, I stumbled upon this phenomenon, which shows two
> >different results as far as the byte allocation is concerned, which I
> >could
> >not comprehend. Any insight would be appreciated.
> >
> >USER_INDEXES
> >************
> >
> >Index Name Table Name Initial Ext Next Ext Min. Ext. PCT
> >Increase
> >---------- ---------- ----------- -------- ---------
> >------------
> >CUST_PK CUSTOMER 36864 40960
> >1 50
> >ORDER_PK ORDER 12288 40960
> >1 50
> >
> >
> >USER_SEGMENTS
> >*************
> >
> >Segment Name Bytes Extents
> >------------ -------- -------
> >CUST_PK 40960 1
> >ORDER_PK 28672 1
> >
> >My question is shouldn't the BYTES column in the USER_SEGMENTS show
> >38684 & 12288.
> >Why is the bytes column displayed as 40960 & 28672, when the formula to
> >calculate
> >the bytes allocated in this case (only one extent allocated) should be
> >
> > (number of extents) X (initial extent)
> >
> >
> >ie., 1 X 36864 = 36864 bytes
> > 1 X 12288 = 12288 bytes
> >
> >Thanks for your time and reply.
> >
> >-Prakash

> I believe you are seeing the difference between what you told Oracle to
> do, and how Oracle is rounding up to fill up multiples of the blocksize.
> --
> These opinions are my own and not necessarily those of Information Quest
> jgarry@eiq.com http://www.informationquest.com
> http://ourworld.compuserve.com/homepages/joel_garry
> "See your DBA?" I AM the @#%*& DBA!
Received on Sun Feb 08 1998 - 00:00:00 CST