Self-Tuning Checkpointing

 

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The new MMAN (Memory Manager) process controls the automatic allocation of the memory within the SGA. Its job (among other things) is to keep track of the sizes of the memory areas, monitor the database and its workload to ensure that memory distribution is optimal, and redistribute memory allocations as required. This is very useful for hybrid databases that have fluctuating demands on memory areas.

Self-Tuning Checkpointing

Oracle Database 10g will now self-tune checkpoint operations so that Oracle Database 10g can make the best use of the I/O bandwidth that is available to the system. To enable self-tuned checkpointing, you should set the fast_start_mttr_ target parameter to a non-zero value. Note that this parameter defaults to 0, which disables self-tuning checkpointing.

New Oracle Database 10g Trace Functionality

Oracle Database 10g offers new trace functionality that makes tracing of user sessions much easier. Now, you can enable tracing of all sessions of a specific user by using the dbms_monitor stored PL/SQL package. The client_id_trace_enable procedure allows you to enable tracing for all sessions started by a specific client. Here is an example of a call to this procedure:

 Exec - dbms_monitor.client_id_trace_enable(client_id=>'PROD_USER'); 

This command will result in the generation of a number of trace files. Oracle Database 10g comes with the new trcsess utility that allows you to scan through all trace files and combine those produced by the user into a single trace file. Here is an example of the trcsess command in action:

 Trcsess output=prod_user.trc clientid='PROD_USER' *.trc 

Note that if you have old trace files, they will be included when the trcsess utility is run. So, if you do not wish to include these files, you need to either move them or rename them with a different extension. You can use the optional waits procedure to generate wait-related information, and the optional binds parameter instructs Oracle Database 10g to include bind variable values in the trace files.

When you enable tracing of a session via the dbms_monitor PL/SQL package, the tracing will appear in the DBA_ENABLED_TRACES view. For example, when we enabled tracing for PROD_USER, the following showed up in the DBA_ENABLED_ TRACES view:

 SQL> select trace_type, primary_id, waits, binds from dba_enabled_traces; 
 


Oracle Database 10g New Features
Oracle Database 10g New Features (Osborne ORACLE Press Series)
ISBN: 0072229470
EAN: 2147483647
Year: 2006
Pages: 80

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