Re: Sizing Indexes - URGENT

Are you actually going to use the formula ? And I thought that Oracle had dropped the formua from recent versions of its RDBMS documentation [8.1 and upwards].

The only real way you can get an approximation [not the exact projection] of the size is to load some data and then analyze the tables. Else, use some "fudge" factors.
Hemant

At 08:08 PM 16-03-03 -0800, you wrote:

>Dear All,
>
>I have a task on hand to size a database for our application. I have used
>the Oracle rule to find out the rowsize of rows in a table.
>
>1. Space available for the data (SAD) = data block size block
>header size = db_block_size kcbh ub4 ktbbh (initrans -1)*
>ktbit kdbh
>2. Available Data Space (ADS) = ceil(SAD * (1-pctfree/100)) kdbt
>3. Space used per row (SPR) = (Total size of the columns data
>length) + (1 byte per column with length < 250 )+ (3 * 1
>byte per column with length >= 250)
>4. Row Size (ROWSZ) = 3 * ub1 + SPR
>5. Space used per row(SPROW) = max(ub1 * 3 + ub4 + sb2, ROWSZ) + sb2
>6. Total Size of the table = Expected Number of records * SPROW
>
>I hope this formula is correct.
>
>How can I do the sizing of indexes. Shouldn't I take into account the 10
>bytes consumed by the ROWID pseudocolumn apart from the column(s) that are
>indexed ?
>
>TIA for all your help.
>
>Best Regards
>Jai

Hemant K Chitale
My personal web site is : http://hkchital.tripod.com

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