Re: Help needed to find table space

I went black when I decided to respond to your request on the size of the fixed header in an Oracle block, but you can find this number in the database administrator's guide.

Multiple the number of rows by the average row length and devide by the available space in a block to get the number of Oracle blocks. Now multiply this by the full Oracle block size to get total bytes needed. This can get divided by 1024 or 1048576 to convert to Kilobytes or Megabytes as desired.

The average row length is calculated by adding up the average column lengths for character fields plus there length bytes (1 < 128 bytes, 3 > 128), numbers are computed as 1 + ceil( no. of digits / 2 ) + 1. Numbers are stored in scientific notation so that is 1 byte for the sign, the digits, and the mantessa (sp). Dates take 7 bytes to store. There are 3 bytes per row of overhead but I added it in the available space per oracle block because I believe that the avg_overhead column of all_tables includes this number.

Available Oracle block size - fixed segment size - ( 23 * no. of initrans ) - (3 bytes per row in the block for row overhead).

This will get you close. Indexes are similiar.

Mark Powell -- The only advise that counts is the advise that you follow so follow your own advise Received on Thu Feb 27 1997 - 00:00:00 CET