pat98's always & forever

How to Set EVENTS in the SPFILE:
================================

You need to set several events in the parameter file. You can perform this task
successfully in the text based parameter file, and need to do the same
operation for an instance that uses the new Oracle9i binary server side
parameter file, also known as the SPFILE.

1)  An example of the text based parameter file syntax is:

      event="10325 trace name context forever, level 10"
      event="10015 trace name context forever, level 1"

    Inserting other parameters between these lines will cause the last
    event only to be included.

2a) One method to set the event in the SPFILE is to use the SQL syntax:

      SQL> ALTER SYSTEM SET
           EVENT='10325 trace name context forever, level 10',
           '10015 trace name context forever, level 1'
           COMMENT='Debug tracing of control and rollback' SCOPE=SPFILE;
 
      System altered.

    The instance must be restarted for the events to take effect.

2b) The instance must have been started with an SPFILE.  Otherwise this ALTER command will fail as follows:

      SQL> ALTER SYSTEM SET
           EVENT='10325 trace name context forever, level 10',
           '10015 trace name context forever, level 1'
           COMMENT='Debug tracing of control and rollback' SCOPE=SPFILE;

      ALTER SYSTEM SET
      *
      ERROR at line 1:
      ORA-32001: write to SPFILE requested but no SPFILE specified at startup

2c) You cannot set the event during the instance life:

      SQL> ALTER SYSTEM SET
           EVENT='10325 trace name context forever, level 10',
           '10015 trace name context forever, level 1'
           COMMENT='Debug tracing of control and rollback' SCOPE=BOTH;
      EVENT='10325 trace name context forever,
      *
      ERROR at line 2:
      ORA-02095: specified initialization parameter cannot be modified

      If you get an error like this, it is necessary to use SCOPE=SPFILE
      and restart the database.

2d) The command can be performed with the instance in NOMOUNT state.
    You can set events without having to open or mount the database.

3) If you need to alter, add or remove an event, you have to enter the
    whole new list in the ALTER SYSTEM command and restart.

4) To remove all events, use:
     
      SQL> ALTER SYSTEM RESET EVENT SCOPE=SPFILE SID='*' ;

      System altered.

    The asterisk ("*") in this example applies to all cases but Real
    Application Cluster.  In a Real Application Cluster configuration
    environment the instance name is required instead of the asterisk.

5) To have events set up immediately, typically for dumping or tracing, use:

      SQL> ALTER SESSION SET EVENTS 'immediate trace name controlf level 2' ;

      System altered.

6) To configure a system-wide "triggered" event, use something like

      SQL> alter system set events '942 trace name ERRORSTACK level 3';

      System altered.

7) To turn off non-immediate system or session events interactively,
    you can use a syntax like the following:

      SQL> alter system set events '942 trace name ERRORSTACK off';

      System altered.

      SQL> alter system set events='10325 trace name context off';

      System altered.



Note the different syntax:
  
- "SESSION" versus "SYSTEM", "EVENTS" versus "EVENT", and no "," before the
   "level" keyword.
- Additionally, you can specify each event in a separate ALTER SESSION command.