Paul Boothroyd wrote:
> ANALYZE TABLE cannot be used, as this is based upon the current content.
> The formulae are there to estimate the disk space requirements for a
> server into the future. This can be quite complicated with variable
> length records.
>
Yes, that is true. Without a crystal ball or an excellent ability with
precognition, no person or software package can *accurately* predict the
future. However, depending on how many rows are in your "current
content," you can make a pretty good guess at future sizes. When you
analyze tables (use the dbms_stats.gather_schema_stats in 8i and above),
one of the statistics produced is the average row length. Multiply that
by the number of rows you expect in the future (again an assumption) and
you'll come close.
That's what I used to do as a physicist ... make all kinds of
assumptions, then predict the outcome. If my assumptions were correct
(or close enough), then the outcome was also close. The model was
considered accurate. In the case of Oracle, you have to assume that with
a large enough sample number of rows that the average row length is a
pretty good assumption.
Received on Mon Jan 20 2003 - 14:46:31 CST
