CONTROL_FILE_RECORD_KEEP_TIME and Performance
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Thread: CONTROL_FILE_RECORD_KEEP_TIME and Performance

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  1. #1
    Join Date
    Apr 2002
    Location
    Phoenix, AZ
    Posts
    175

    CONTROL_FILE_RECORD_KEEP_TIME and Performance

    Secnario:

    1. Very High Update Activity on the Database
    2. High number of Log Switches are occuring
    3. Saw "denied expansion of controlfile section" in Alert.Log
    4. Saw that CONTROL_FILE_RECORD_KEEP_TIME = 7 Days
    5. Changed it to 0

    My question:

    1. What exactly happens if control file records = 65535 and new log switches are occuring.

    2. How does this affect performance.

    I've tried to get answers from Metalink, but could not get the answers.

    Any insights very helpful.

    Thanks
    Sridhar
    Sridhar R Patnam

  2. #2
    Join Date
    May 2002
    Posts
    2,645
    Your controlfile is written to anyway. What performance hit would you expect? The record is written over, you get an alert message in the alert.log, so how much of a performance hit do you think that is? Miniscule?

    The default value for CONTROL_FILE_RECORD_KEEP_TIME is 7 days. SQL> select value from v$parameter
    2 where name='control_file_record_keep_time';

    VALUE
    -----
    7

    * the MAXLOGHISTORY database parameter has already reached the maximum of 65535 and it cannot be increased anymore.

    The MAXLOGHISTORY increases dynamically when the CONTROL_FILE_RECORD_KEEP_TIME is set to a value different from 0, but does not exceed 65535. Once reached, the message appears in the alert.log warning you that a controlfile record is written over.

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