Fw: impact of changing optimizer_features_enable

From: Fuad Arshad <fuadar@xxxxxxxxx>
To: oracle-l@xxxxxxxxxxxxx
Date: Sat, 23 Jun 2007 07:26:51 -0700 (PDT)

----- Forwarded Message ----
From: Fuad Arshad <fuadar@xxxxxxxxx>
To: ujang.jaenudin@xxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxx
Sent: Saturday, June 23, 2007 9:25:27 AM
Subject: Re: impact of changing optimizer_features_enable

if you have jonathan lewis' bookcost based optimizer . he devotes a whole 
chapter/appendix on this subject as to what changes.
i am using  this for my application. the good thing about 10.2 is that thisis a 
session level parameter so you can actually code a trigger. i'm on  9i and this 
is a system setting which disables all 9i features including system statistics 
etc.
 you can actuially go and look at each _ parameter and tryot find which 
parameter might be the cause .or do a 10053 trace and see what parameters itis 
using with optimizer_features_enable=10.2 vs optimizer_features_enable=8.1.7
this will pretty much bringyou to the parameter changes internally and might 
lead you to a solution.

----- Original Message ----
From: Ujang Jaenudin <ujang.jaenudin@xxxxxxxxx>
To: oracle-l@xxxxxxxxxxxxx
Sent: Friday, June 22, 2007 11:10:07 PM
Subject: impact of changing optimizer_features_enable

all,

i have a funny things about how oracle given execution plan.

now my db is 10.2.0.3 on itanium 64bit.
when tried *.optimizer_features_enable from 10.2 until 9.2 , the
report was not much different (so slow). but when change to
*.optimizer_features_enable=8.1.7, it amazingly so so so fast....

so, does anyone have experiences about changing the above parameter
and the impact to the applications?

thanks for your sharing...

-- 
regards
ujang
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//www.freelists.org/webpage/oracle-l

Fw: impact of changing optimizer_features_enable

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