Re: Oracle 8i server vs Oracle 8i EE

From: <nlzanen1_at_EY.NL>
Date: Wed, 13 Jun 2001 04:11:40 -0700
Message-ID: <F001.003273F0.20010613033045@fatcity.com>

Hi,

AFAIK the number of CPU's is also importatnt for the optimizer. You go from 4 CPU's to 1 CPU (Correct?) it seems logical to me that the explain plan will be different. (Hash join is memory intensive Nested loop are CPU intensive).

If you want same explain plan use hints to force nested loops.

Jack

                                                                                       
                               
                    "Allan Robertson"                                                  
                               
                    <robertson_allan_at_ho       To:     Multiple recipients of list 
ORACLE-L <ORACLE-L_at_fatcity.com>     
                    tmail.com>                cc:     (bcc: Jack van 
Zanen/nlzanen1/External/MEY/NL)                  
                    Sent by:                  Subject:     Oracle 8i server vs Oracle 
8i EE                           
                    root_at_fatcity.com                                                   
                               
                                                                                       
                               
                                                                                       
                               
                    13-06-2001 12:36                                                   
                               
                    Please respond to                                                  
                               
                    ORACLE-L

I have recently been called onto a client site where they are having some performance issues with an OLTP db.

If I outline the situation you will see some of the obvious problems, but I

having a couple of problems identifying the reason for differences in the execution path of a couple of important queries and was wandering if anyone

knew of implementation difference between Enterprise Edition and Server regarding the CBO or any CBO bugs in an unpatched install of 8.1.6.0.

Environment
Development Instance
Quad 400MHz NT server with Oracle 8i 8.1.6.0 EE, 1.5GB mem and 2 disks.

To be Production instance
Single 933MHz NT server with Oracle8i 8.1.6.0 8 disks in a RAID 1 stripe.

Instance data the same and all analyzed. Init parameters the same.

queries involve outer joins between 4 small and one large table. Run time on development is 5 seconds. On the "go live" server I have brought
it down to 20secs from 2 minutes by increasing the sort_area_size. I am looking at reducing hash_area_size on the production instance to sort_area_size as it appears to be favouring a hash join over nested loops.

I have limited access to the client and time availavble so want to avoid 10053 traces at present.

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Author: Allan Robertson
INET: robertson_allan_at_hotmail.com

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INET: nlzanen1_at_EY.NL

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