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RE: [Q] ORACLE 9i fast_start_mttr_target and log_checkpoint_inte

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Tue, 19 Nov 2002 05:58:55 -0800
Message-ID: <F001.0050676F.20021119055855@fatcity.com>


Dist -

   Since nobody seems to have responded, I'll take a crack at it. The Oracle9i documentation specifically says (in the Oracle9i Database Reference) that either FAST_START_IO_TARGET or LOG_CHECKPOINT_INTERVAL will override FAST_START_MTTR_TARGET. I would tend to believe them.

    In the Oracle9i Performance Tuning Guide, Oracle contains a note that you should disable or remove the FAST_START_IO_TARGET, LOG_CHECKPOINT_INTERVAL, and LOG_CHECKPOINT_TIMEOUT parameters when using FAST_START_MTTR_TARGET. Setting these parameters interferes with FAST_START_MTTR_TARGET.
    I don't see where LOG_CHECKPOINTS_TO_ALERT would cause a problem, but if you are suspicious, you might check metalink.

    As I understand it, the big advantage of FAST_START_MTTR_TARGET is its ease and accuracy. Your management provides a goal for how long your Oracle database can take to recover in the situation where it crashes. You simply convert that number to seconds and set FAST_START_MTTR_TARGET. With the LOG_CHECKPOINT parameters, the settings are derived more indirectly.

   Of course, there is no free lunch. Setting a shorter recovery time may interfere with performance.
Dennis Williams
DBA, 40%OCP
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Monday, November 18, 2002 11:04 AM To: Multiple recipients of list ORACLE-L log_checkpoint_interval parameter?

I saw a document mention if log_checkpoint_interval define on ORACLE 9i, the fast_start_mttr_target parameter will be ignore. My question is:

  1. we have following on init.ora file:
    log_checkpoint_interval = 10000
    log_checkpoint_timeout = 1800
    log_checkpoints_to_alert = true

    fast_start_mttr_target=300

Do I need remove all the log_checkpoint* on init.ora file?

2. what kind of benefit that fast_start_mttr_target better than log_checkpoint* ?

Thanks



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Author: DENNIS WILLIAMS
  INET: DWILLIAMS_at_LIFETOUCH.COM
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