I like to think of it this way:
If a table is defined as "small" when it does not need
to be indexed, then there is no such thing as a small
table
Others didn't mention - but you may want to look at
using IOT's for some of the cases you've mentioned
Cheers
Connor
- "Jesse, Rich" <Rich.Jesse_at_qtiworld.com> wrote: >
Actually, I did know about the BHR thing, primarily
> from this list, just as
> you did. It was the indexing one that cought me
> off-guard. I was just
> using the former as a reference.
>
> Speaking of which, your Don Quixote reference is
> priceless! "Facts are the
> enemy of truth." :D
>
> Rich Jesse System/Database
> Administrator
> Rich.Jesse_at_qtiworld.com Quad/Tech
> International, Sussex, WI USA
>
> > -----Original Message-----
> > From: DENNIS WILLIAMS
> [mailto:DWILLIAMS_at_LIFETOUCH.COM]
> > Sent: Monday, November 11, 2002 2:04 PM
> > To: Multiple recipients of list ORACLE-L
> > Subject: RE: Is nothing sacred? (Oracle vs The
> Experts)
> >
> >
> > Rich - Actually, if you took an Oracle Performance
> Tuning
> > class from Oracle
> > Education right now, you would find the BHR
> mentioned little
> > and Oracle
> > waits emphasized a great deal. I took that class
> about a
> > month ago and the
> > instructor described how Cary had prevailed in
> convincing the
> > people at
> > Oracle that counted and the class materials were
> being
> > rewritten for the
> > next class after mine.
> > Well, being a computer professional is a hard
> burden, what with the
> > underlying assumption ever changing. Actually,
> given the extensive
> > discussions we've had on this forum about BHR vs.
> waits, I'm
> > surprised it
> > caught you unawares. This was where I'd first
> heard about the
> > new emphasis
> > on waits. Of course, with waits becoming the
> conventional
> > wisdom, Cary and
> > others will have to find another windmill to tilt
> at. Cary -
> > anything lined
> > up?
> > Dennis Williams
> > DBA, 40%OCP
> > Lifetouch, Inc.
> > dwilliams_at_lifetouch.com
> >
> >
> > -----Original Message-----
> > Sent: Monday, November 11, 2002 10:58 AM
> > To: Multiple recipients of list ORACLE-L
> >
> >
> > So, there I am, on 8.1.7.2 (and .4) on HP/UX 11.0,
> with a
> > process that runs
> > 20 minutes out of every hour of the day (despite
> my protests to it's
> > design). After it starts having problems (go
> figure), it
> > becomes a priority
> > to speed it up.
> >
> > Thanks to a 10046 trace, we see that the query
> taking the
> > most elapsed time
> > does FTSs on each of two very small tables (1
> block and 4 blocks -- 8K
> > blocksize). These tables are not indexed, as per
> the official Oracle
> > recommendation. After reading the excellent
> Hotsos paper
> > "When to index a
> > table" (THANKS, CARY!), I added an index to reduce
> elapsed
> > time on this
> > query by 50% (150 to 75 seconds in test), proving
> to me that
> > the paper is
> > valid. And I've only read to page four!
> >
> > OK, first I'm taught by Oracle to look at Buffer
> Cache Hit Ratios as a
> > measure of performance, then told (and thoroughly
> convinced)
> > by experts that
> > this is bunk. Now, I found out that the 15% (or
> 10% or
> > whatever, depending
> > on version) ratio of rows returned to total rows
> in
> > determining when to use
> > an index in a query is garbage.
> >
> > 1) Why is this?
> >
> > 2) What other pearls of performance wisdom from
> Oracle Corp should I
> > completely disregard as false?
> >
> > I know there's an Oracle Fallacy website
> somewhere...
> >
> > It just looks bad on me, our department, and
> Oracle when, once again,
> > something I've been preaching to our developers as
> gospel
> > turns out to be
> > completely false.
> >
> > Maybe I'm grumpy because it's snowing on my leaves
> right
> > now... <sigh>
> >
> >
> > Rich
> --
> Please see the official ORACLE-L FAQ:
> http://www.orafaq.com
> --
> Author: Jesse, Rich
> INET: Rich.Jesse_at_qtiworld.com
>
> Fat City Network Services -- 858-538-5051
> http://www.fatcity.com
> San Diego, California -- Mailing list and web
> hosting services
>
> 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
> (or the name of mailing list you want to be removed
> from). You may
> also send the HELP command for other information
> (like subscribing).
Connor McDonald
http://www.oracledba.co.uk
http://www.oaktable.net
"GIVE a man a fish and he will eat for a day. But TEACH him how to fish, and...he will sit in a boat and drink beer all day"
Do You Yahoo!?
Everything you'll ever need on one web page
from News and Sport to Email and Music Charts
http://uk.my.yahoo.com
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: =?iso-8859-1?q?Connor=20McDonald?=
INET: hamcdc_at_yahoo.co.uk
Fat City Network Services -- 858-538-5051 http://www.fatcity.com
San Diego, California -- Mailing list and web hosting services
---------------------------------------------------------------------
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
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
Received on Mon Nov 11 2002 - 16:13:32 CST
