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��������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

>

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  • Jonathan Lewis at Jan 2, 2003 at 10:29 am
    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.uk

    Coming 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.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
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    (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.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
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    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
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  • Rachel Carmichael at Jan 2, 2003 at 10:48 am
    what makes you think you have "excessive redo" being generated? What
    does the application do? How many changes are made daily? How
    frequently? Just because a tablespaces is locally managed does not mean
    there will be no redo generated when a change is made, it just means
    that there will be less activity in the SYSTEM tablespace.

    VIVEK_SHARMA wrote:
    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.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
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    also send the HELP command for other information (like subscribing).
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    Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
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    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Rachel Carmichael
    INET: wisernet100_at_yahoo.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
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    (or the name of mailing list you want to be removed from). You may
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postedJan 2, '03 at 7:08a
activeJan 2, '03 at 10:48a
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