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5 Replies Latest reply: Sep 22, 2009 3:52 AM by Marko Sutic RSS

Who writes alert log file?

swapnil kambli Journeyer
Currently Being Moderated
Hi guys ,

I have been searching for answer to this question,.............

Which process(backgroud process) writes to alert log file?
  • 1. Re: Who writes alert log file?
    Hemant K Chitale Oracle ACE
    Currently Being Moderated
    Not "one" but all the background processes can / do write to it.

    The archiver writes to it. LogWriter can write (if you have log_checkpoints_to_alert).
    When a background process detects that another has died, the former writes to the alert log before panicking the instance and killing it.

    Similarly an ALTER SYSTEM command issued by the server process for your database session will also write to the alert.log

    (You can also invoke a specific database procedure to write to it -- but this is not documented).


    Hemant K Chitale
  • 2. Re: Who writes alert log file?
    515958 Pro
    Currently Being Moderated
    (You can also invoke a specific database procedure to write to it -- but this is not documented).
    Hemant, will you please share this. What are the circumstances when we do that.

    Regards,
    S.K.
  • 3. Re: Who writes alert log file?
    swapnil kambli Journeyer
    Currently Being Moderated
    hemant,

    then what is the diffrence between the trace files they write and what they write in alert log
    (I am a newbie)
  • 4. Re: Who writes alert log file?
    Hemant K Chitale Oracle ACE
    Currently Being Moderated
    Trace files for user processes are normally in the user_dump. They are created only when tracing is requested OR when Oracle encounters an error.

    The alert.log is a file that is used to continously display the status of the database as it changes with important events (e.g. archival of log, alter system commands, ora-1555 errors, indexes unusable, datafile space allocation etc). Most of these are issues which affect the entire instance/database. However, where a sever error is encountered in a user process, Oracle writes a trace file in user_dump_dest for that error and a message indicating the error and the name of the trace file to the alert.log.

    Similarly, the background processes may also be writing to their own trace files to indcate status /tracing.

    The level of detail being logged can vary by version and by setting specific database events (if specified by Oracle Support) in the instance.

    See http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/manproc.htm#sthref729

    Hemant K Chitale
  • 5. Re: Who writes alert log file?
    Marko Sutic Newbie
    Currently Being Moderated
    Santosh,

    follow this link [Write message to alertlog|http://www.oracle.com/technology/oramag/code/tips2003/011203.html].

    Regards,
    Marko

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