RE: measuring the size of updates

Thanks.

I like your position title!

: )

Patrice Boivin
Systems Analyst (Oracle Certified DBA)

	-----Original Message-----
	From:	Jeffery Stevenson [SMTP:jeff_at_mpv.com]
	Sent:	Monday, July 10, 2000 1:38 PM
	To:	Multiple recipients of list ORACLE-L
	Subject:	RE: measuring the size of updates

	You could invest in a log-reading utility and then you could profile
off of
	the exact update statements that went against the tables (requires
money,
	but then again, your time spent working on this is money as
well...it's all
	a matter of justification).  I usually don't get that precise with
my
	calculations for PCTFREE unless there is a problem that wasn't
accounted for
	at design time (like the DB_BLOCK_SIZE being to small for the
database needs
	or application driven denormalizations that require huge amounts of
updates
	to "fill in" data from the application to the database).  These are
just
	some things you might want to look into...

	Jeffery Stevenson
	Chief Database Geek
	Medical Present Value, Inc.
	Austin, TX

	-----Original Message-----
	Patrice J
	Sent: Monday, July 10, 2000 8:34 AM
	To: Multiple recipients of list ORACLE-L


	In my Oracle7.3. Performance Tuning course, they mentioned that to
reduce
	migration we should set PCTFREE properly.

	They also provided the following formula:

	PCTFREE =3D 100 * [ avg. size of updates  /  (avg. size of updates +
initial
	row length) ]

	It occurred to me that since Oracle didn't explain how we should go
about
	doing this, maybe I should ask.  Our instructor said I should use
Pre Update
	and Post Update triggers to keep track of this, but he didn't go
into
	detail.

	Has anyone done this successfully?

	What was the impact on performance?

	I want to incorporate this calculation into my weekly PT script, if
	possible.

	TIA
	Patrice Boivin
	Systems Analyst (Oracle Certified DBA)

	Systems Admin & Operations | Admin. et Exploit. des syst=E8mes
	Technology Services        | Services technologiques
	Informatics Branch         | Direction de l'informatique
	Maritimes Region, DFO      | R=E9gion des Maritimes, MPO

	E-Mail: boivinp_at_mar.dfo-mpo.gc.ca <mailto:boivinp_at_mar.dfo-mpo.gc.ca>

	--
	Author: Boivin, Patrice J
	  INET: BoivinP_at_mar.dfo-mpo.gc.ca

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	--=20
	Author: Jeffery Stevenson
	  INET: jeff_at_mpv.com

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