Log-apply services require memory the shared pool

begin sys.dbms_logmnr_d.set_tablespace('log_ts'); end;

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create spfile from pfile;

The logical standby can be cloned from the primary either following a clean shut-down of the primary or while the primary database is up and running. If the primary is to remain up, the database Resource Manager must be running. This can be enabled using the following SQL:

To ensure the fastest application of redo on the standby, log-apply services require memory in the shared pool, and the use of parallel query. By default, 25 percent of SGA memory on the standby is allocated for redo-apply operations. Therefore, considera-tion should be given to increasing the SGA on the standby instance compared with that on the primary. The APPLY_SET procedure in the DBMS_LOGSTDBY package is used to control resource allocation. The following command restricts the SGA usage for redo log application on the standby to the specified limit:

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REM select * from DBA_LOGSTDBY_PARAMETERS show APPLY_SET values

Creating the Logical Standby

The logical standby database must be based on a copy of the primary. This copy can be taken either following a clean shutdown of the primary (using either SHUTDOWN or SHUTDOWN IMMEDIATE) or while the primary database is up.