Re: percent used property of table

Richard Elliott wrote:

> As I understand it this means a table with the default value of 40%
> will never have a row inserted into any block for that table unless
> there is at least 40% free space in that block as a result of
> deletions. Why would the default be so low ?, and does it make good
> sense to use a much higher value if the table is one that normally has
> a lot of inserts and deletes performed against it in the normal course
> of processing?
>
> Trying to understand why some of my tables have high disk read ratios,
> and I find the same tables have lots of blocks, many many more blocks
> than can be explained by the number and length of rows.
>
> Am I on the right track ?

The default values provided by Oracle are almost always bad values. You must calculate PCTFREE and PCTUSED on a case-by-case table-by-table basis based on your specific application and data.

-- 
Daniel Morgan
http://www.outreach.washington.edu/ext/certificates/oad/oad_crs.asp
http://www.outreach.washington.edu/ext/certificates/aoa/aoa_crs.asp
damorgan_at_x.washington.edu
(replace 'x' with a 'u' to reply)