Oracle Database 11 g - Online Public Access Catalog

434 CHAPTER 10 ■ DATA GUARDDynamically Set the Data Guard SQL Apply ParametersTraditionally the DBMS_LOGSTDBY.APPLY_SET procedure was used to set Oracle database initializationparameters. The negative aspect of this procedure was that the SQL Apply engine hadto be shut down. Oracle Database 11g lifts this restriction, and the apply_set procedure can setthese parameters without stopping SQL Apply:• apply_servers• event_log_dest• log_auto_del_retention_target• log_auto_delete• max_events_recorded• max_servers• max_sga• prepare_servers• record_applied_ddl• record_skip_ddl• record_skip_errors• record_unsupported_operationsFor example, you can now dynamically adjust the number of parallel servers used by SQLApply to ten without bouncing the SQL Apply engine:SQL> exec dbms_logstdby.apply_set ('MAX_SERVERS', 10);PL/SQL procedure successfully completed.In Oracle Database 11g, new columns, UNIT, SETTING, and DYNAMIC, are added to the DBA_LOGSTDBY_PARAMETERS view. This view provides the list of parameters used by the SQLApply engine. The SETTING column shows parameters set as default or those modified by theDBAs. The value of system indicates that the parameter was not explicitly set by a DBA. TheUNIT column displays the unit of value when applicable. The DYNAMIC column provides informationon whether the SQL Apply parameter must be shut down to activate. By querying thisview, you can see that the preserve_commit_order parameter is the only parameter that is notdynamically modifiable:SQL> select *2 from dba_logstdby_parameters3* order by nameSQL> /