Oracle DBA

This parameter controls the maximum amount of memory PGA which can be used by the queries when WORKAREA_SIZE_POLICY is set to Auto.

The value you can be set in Bytes, kilobytes (K), megabytes (M) or gigabytes (G). The default value is 0

This parameter also has an effect on the execution plans of the cost based optimizer. The optimizer uses the value of the parameter PGA_AGGREGATE_TARGET to derive an estimate

for the minimum and maximum amount of memory which should be available at run-time for each sort, hash-join and bitmap operator in the query. Based on this minimum and maximum value, the

optimizer selects the best plan.

DBMS_STATS.GATHER_TABLE_STATS with GRANULARITY => 'PARTITION' OPTION

Wait is due to Data Guard Broker.

Can't change CHARACTERSET of a database, you will need to re-create the database with

appropriate CHARACTERSET.

All Archivelogs

1. Modify init.ora parameter START_ARCHIVE=TRUE

2. SQL> SHUTDOWN IMMEDIATE;

3. STARTUP MOUNT;

4. ALTER DATAVASE ARCHIVELOG;

5. ALTER DATABASE OPEN;

By turning MONITORING ON that index and querying into INDEX_USAGE table

By setting FORCE LOGGING to TRUE, all transactions will generate REDO. This is used for Data Guard, so no data will be missed (i.e. transactions that were run with NOLOGGING option) in Standby database

Yes we have to enable archive log because archive log are going to apply in standby database.

System table space and it's contents are created a part of database creation and contains the meta data of the database. I do not see any reason why one would want to export and import contents only the SYSTEM table space. It can be part of the full database export/import.