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Home -> Community -> Mailing Lists -> Oracle-L -> RE: OT: Misinformation Ranting
It was not until late 7 (7.3?) that you could use query parallelism.
Multiple extents is a plus for query parallelism.
-----Original Message-----
From: Freeman, Robert [mailto:Robert_Freeman_at_csx.com]
Sent: Tuesday, September 10, 2002 4:15 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: OT: Misinformation Ranting
Also along in the 7 days you had a ceiling on the maximum number of extents associated with the block size. So, in some cases, there was a practical reason to rebuild a table to fit in one extent.
RF
Robert G. Freeman - Oracle OCP
Oracle Database Architect
CSX Midtier Database Administration
Author
Oracle9i RMAN Backup and Recovery (Oracle Press - Oct 2002)
Oracle9i New Features=A0(Oracle Press)
Mastering Oracle8i=A0 (Sybex)
The avalanche has begun, It is too late for the pebbles to vote.
-----Original Message-----
Sent: Tuesday, September 10, 2002 5:17 PM
To: Multiple recipients of list ORACLE-L
Jared,
What version of the database does this book refer to? I do =
remember
back in
Version 6 and early 7 that having all of your data for a table and/or =
index
all
in the first extent was a performance benefit. Regrettably that idea =
had
been
proved false more than once after 7.2 hit the street. I notice a
performance
improvement if tables/indexes are in more than one extent. But if =
she's
talking
about migrated and/or chained rows that's another matter & one that I'm
chasing
as I type.
Looks like you've got a classic case of someone with enough =
information
to
be dangerous.
Dick Goulet
____________________Reply Separator____________________ Author: Jared.Still_at_radisys.com Date: 9/10/2002 12:28 PM
<RANT>
I've just spent 30 minutes with our SAP administrator trying to convince her that we really don't need to reorganize the tables in our production SAP database.
Due to some misinformation in an Oracle Press book, 'Oracle Unleashed' I think, she is equating number of extents with fragmentation.
The text she referred me to is in fact discussing 'migrated rows' =
though
that term is never used. She has become convinced that if the
extents allocated for tables are not all in contigous space, some
very nasty fragmentation will occur.
I tried taking it down to disk and explaining that an OLTP system with=20 hundreds of users won't really see much benefit from this, but she wasn't really ready for that. :)
Her concern is that there are 29000 extents in an index tablespace. This might have something to do with there being 3400 indexes in said tablespace.
Total 'wasted' ( honeycomb ) space in this 250 gig DB is < 20 meg. Not much to gain there.
The text of the book states that you should expect a '10 to 20 percent=20 performance increase' by reorganizing the tables/indexes. No data to=20 back it up of course.
This is on a database that performs very well most of the time, outside of a couple of custom reports that run too long. No complaints from users about slowness.
Arrghhh!
I just had to vent to the list, cuz there's no one here that = understands.
<\RANT>
Jared
--=20
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--=20
Author:=20
INET: Jared.Still_at_radisys.com
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Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists --------------------------------------------------------------------To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L Received on Tue Sep 10 2002 - 16:27:31 CDT
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