Re: Tablespace
Date: 9 Jun 92 01:03:09 GMT
Message-ID: <2345_at_iris.mincom.oz.au>
I use the following calc to estimate storage:
ts:
block header = fixed header / footer + table directory +
variable transaction header
fixed header = 57
table directory = 4 * number of tables
var trans header = 23 * INITRANS
available data space = ( blocksize - block header ) * (100 -PCTFREE)/100
Minimum row size is 9
rows per block = (available space)/(max(9,avg_row_length)+row_directory)
index:
blocks = 1.01 * ( not null rows * avg entry length ) /
( floor ( block_space / avg entry length ) ) * avg entry length block space = ( block size - 113 - INITRANS * 23 ) * (100 - PCTFREE) / 100 avg entry length = 10 + number of columns + average length of all columns
[ + 1 if unique ]
Thanks to a bulletin using a paper from Adre Bakker and Jon Klein.
-- Hans-J Plambeck Mincom Pty Ltd hans_at_mincom.oz.au +61 (7) 364 9999Received on Tue Jun 09 1992 - 03:03:09 CEST