1. Explain FORCE LOGGING feature in 9i.

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

2. How can you tell if an index on particular table is USED or NOT USED in 9i?

By turning MONITORING ON that index and querying into INDEX_USAGE table

3. How do you put database is ARCHIVELOG mode, explain procedure?

1. Modify init.ora parameter START_ARCHIVE=TRUE
2. SQL> SHUTDOWN IMMEDIATE;
3. STARTUP MOUNT;
4. ALTER DATAVASE ARCHIVELOG;
5. ALTER DATABASE OPEN;

5. Explain procedure to Change CHARACTERSET of a database.

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

7. How do you analyze table partition using Oracle provided package?

DBMS_STATS.GATHER_TABLE_STATS with GRANULARITY => 'PARTITION' OPTION

8. What is PGA_AGGREGATE_TARGET?

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.

9. List five most important parameter in 9i affecting performance?

CURSOR_SHARING
DB_CACHE_SIZE
PGA_AGGREGATE_TARGET
DB_16K_CACHE_SIZE, DB_8K_CACHE_SIZE, DB_2K_CACHE_SIZE