Sizing Indexes - URGENT

[JayK]

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