In article <38EDF013.B039BDC9_at_dteenergy.com>,
Gregory P Lechkun <lechkung_at_dteenergy.com> wrote:
>
> --------------796931C59B998121866E5321
> Content-Type: text/plain; charset=us-ascii
> Content-Transfer-Encoding: 7bit
>
> Hello,
>
> I'm tuning a table for size, extents, pctfree, and pctused. Here are
> some of the statistics on the table:
>
> block_size 8192
> initial_extent 16384
> next_extent 1048576 -- This was originally 8192 before it was
> adjusted
> max_extents 505
> num_rows 35698
> blocks 315
> empty_blocks 60
> avg_space 3011
> avg_row_len 42
> pctfree 10
> pctused 40
>
> Now, in this table, every row will eventually be deleted. The table
is
> being used as a circular buffer in a FIFO manner, and rows are never
> updated, just deleted. Presently, the oldest row in the table is
dated
> March 12, but a majority of the rows will be cleared out within 7-10
> days. This table will start off at the 35,000 rows and within a year
> will have 1,000,000 rows.
>
> I'm figuring I'm going to set the initial_extent & next_extent to
> 1048576, and setting the pctfree = 5 and pctused = 90 (Kevin Loney's
DBA
> Handbook suggest pctused should be 95-pctfree).
>
> - Does this sound reasonable for a table that has such volatile data?
> - Will having such values in the pctfree & pctused cause a performance
> issue?
>
> --
> Regards,
> Greg Lechkun
> gpl :-)
>
> DTE
>
Energy==================================================================
==
>
> DTE ////// //////////// Gregory Lechkun - EM&D/PDO-PT
> DTE // // // // Power Application Software Engineer
> DTE // // // //// lechkung_at_detroitedison.com
> DTE // // // // g.p.lechkun_at_ieee.org (personal)
> DTE ////// // ////// (313)235-9445 Office (313)940-3306
> Pgr.
> (313)235-8597 FAX
>
What is reasonable like beauty is in the eye of the beholder, but I
think what you have chosen is reasonable. It would appear from the
data you have given that the table will consume about 35M of space so
why not use a larger initial and maybe next size, say 10M. Just a
thought.
--
Mark D. Powell -- The only advice that counts is the advice that
you follow so follow your own advice --
Sent via Deja.com http://www.deja.com/
Before you buy.
Received on Sat Apr 08 2000 - 00:00:00 CDT
