How are you deciding that you are
generating excessive redo ?
What is excessive for 1,500 concurrent
users in a banking operation ?
Using log miner to examine the problem
sounds like a very painful last resort.
Have you taken snapshots of session stats
to try and pin down any patterns to redo
generation so that you can (possibly) associate
large volumes with specific processes ?
Have you tried comparing redo size with
commit / rollback counts to see if there
is any pattern to activity that shows you
were the most redo is generated ?
Couple of thoughts: if your banking application
is typical, then code to update a field on screen
may be turned into SQL to update every single
column in the table - this generates a lot of undo
and redo (especially on wide tables).
If you banking appliation is typical, then it could
spend a lot of its time generating scratch data
in working tables, then rolling it back or deleting
it. This generates a lot of undo and redo.
Both issues can be corrected, but only if you have
access to source, or very compliant suppliers.
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.ukComing soon a new one-day tutorial:
Cost Based Optimisation
(see
http://www.jlcomp.demon.co.uk/tutorial.html )
Next Seminar dates:
(see
http://www.jlcomp.demon.co.uk/seminar.html )
____England______January 21/23
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html-----Original Message-----
To: Multiple recipients of list ORACLE-L
Date: 02 January 2003 07:52
We seem to Be Generating Excessive Redo .
All Tablespaces are LOCALLY Managed except SYSTEM .
Size of Redo Logfile = 200 MB
log_check_point_interval = 300000
log_checkpoint_timeout = 0
log_buffer = 2MB
NOTE - We have purposely kept increased log_check_point_interval =
300000 based on past experience .
Any /etc/system, init.ora parameter Changes too ?
Concurrent Oracle processes = 1500 Approx.
Machine Box = SF6800
Application = Banking (Hybrid )
Oracle 8.1.7.4
Solaris 8
We shall be taking Logminer Outputs
Anything in particular to Look for in the Logminer Output to Check
for Excessive Redo Generation ?
[VIVEK_SHARMA] Thanks
--
Please see the official ORACLE-L FAQ:
http://www.orafaq.net--
Author: VIVEK_SHARMA
INET: VIVEK_SHARMA_at_infosys.com
Fat City Network Services -- 858-538-5051
http://www.fatcity.comSan 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).
--
Please see the official ORACLE-L FAQ:
http://www.orafaq.net--
Author: Jonathan Lewis
INET: jonathan_at_jlcomp.demon.co.uk
Fat City Network Services -- 858-538-5051
http://www.fatcity.comSan 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).