Re: create_index_cost procedure

From: <genegurevich_at_discover.com>
Date: Tue, 7 Jul 2009 09:05:35 -0500
Message-ID: <OFE03037D8.B35A4BE9-ON862575EC.004CE4B9-862575EC.004D6DB7_at_discover.com>



Jonathan:

Now that I have reread your article, I think my question is the same as you raised:
" 24,000 bytes as the used bytes – and that should fit comfortably inside a single 64KB extent in the systemtablespace – so why was the allocated space reported as 128KB / two extents?:

And your answer seems to be that this number does not include the various overheads as well as other factors that could affect the size. Does that mean that it is allocated bytes that should be considered a rough estimate in your opinion?

thank you

Gene Gurevich

                                                                           
             "Jonathan Lewis"                                              
             <jonathan_at_jlcomp.                                             
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Allocated Bytes = 1,735,000,064 = 13,237 extents @ 128KB
Allocated Bytes = 1,736,441,856 =    828 extents @ 2MB
Allocated Bytes = 1,740,636,160 =    166 extents @ 10MB
Allocated Bytes = 1,782,579,200 =     34 extents @ 50MB

Notice that the change from one figure to the next is less than the larger of the two extent sizes. Note also that each figure is an exact multiple of the extent size.

Oracle is rounding up to allow for the unused portion of the last extent.

Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com

Author: Cost Based Oracle: Fundamentals http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

  • Original Message ----- From: <genegurevich_at_discover.com> To: <jonathan_at_jlcomp.demon.co.uk> Cc: <oracle-l_at_freelists.org>; <oracle-l-bounce_at_freelists.org> Sent: Monday, July 06, 2009 11:26 PM Subject: Re: create_index_cost procedure

> Jonathan:
>
> Here is my output :
>
> Allocated Bytes = 1740636160
>
> Allocated Bytes = 1735000064
>
> Allocated Bytes = 1736441856
>
> Allocated Bytes = 1782579200
>
> TABLESPACE_NAME BLOCK_SIZE INITIAL_EXTENT NEXT_EXTENT
> LOGGING ALLOCATIO EXTENT_MAN
> ------------------------------ ---------- -------------- -----------
> --------- --------- ----------
> USERS 16384 131072 131072
> LOGGING UNIFORM LOCAL
> PCM_D_03 16384 2097152 2097152
> LOGGING UNIFORM LOCAL
> UNICA_X_01 16384 10485760 10485760
> LOGGING UNIFORM LOCAL
> UNICA_D_01 16384 52428800 52428800
> LOGGING UNIFORM LOCAL
>
> thank you
>

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Please consider the environment before printing this email. i0zX+n{+i^ Received on Tue Jul 07 2009 - 09:05:35 CDT

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