In your multitenant container database (CDB) containing pluggable database (PDBs), you granted the CREATE TABLE privilege to the common user C # # A_ADMIN in root and all PDBs.
You execute the following command from the root container: SQL > REVOKE create table FROM C # # A_ADMIN; What is the result?

Correct Answer:A
REVOKE ..FROM
If the current container is the root:
/ Specify CONTAINER = CURRENT to revoke a locally granted system privilege, object privilege, or role from a common user or common role. The privilege or role is revoked from the user or role only in the root. This clause does not revoke privileges granted with CONTAINER = ALL.
/ Specify CONTAINER = ALL to revoke a commonly granted system privilege, object privilege on a common object, or role from a common user or common role. The privilege or role is revoked from the user or role across the entire CDB. This clause can revoke only a privilege or role granted with CONTAINER = ALL from the specified common user or common role. This clause does not revoke privileges granted locally with CONTAINER = CURRENT. However, any locally granted privileges that depend on the commonly granted privilege being revoked are also revoked.
If you omit this clause, then CONTAINER = CURRENT is the default. References:

Which statement is true about redo log files during instance recovery?

Correct Answer:C
References https://docs.oracle.com/cd/A58617_01/server.804/a58396/ch2.htm

To enable faster incremental backups, you enabled block change tracking for the database. Which two statements are true about the block change tracking file? (Choose two.)

Correct Answer:CD

Examine the parameters for your database instance:

Which three statements are true about the process of automatic optimization by using cardinality feedback? (Choose three.)

Correct Answer:ACD
C: During the first execution of a SQL statement, an execution plan is generated as usual.
D: if multi-column statistics are not present for the relevant combination of columns, the optimizer can fall back on cardinality feedback.
(not B)* Cardinality feedback. This feature, enabled by default in 11.2, is intended to improve plans for repeated executions.
optimizer_dynamic_sampling optimizer_features_enable
* dynamic sampling or multi-column statistics allow the optimizer to more accurately estimate selectivity of conjunctive
predicates. Note:
* OPTIMIZER_DYNAMIC_SAMPLING controls the level of dynamic sampling performed by the optimizer. Range of values. 0 to 10
* Cardinality feedback was introduced in Oracle Database 11gR2. The purpose of this feature is to automatically improve plans for queries that are executed repeatedly, for which the optimizer does not estimate cardinalities in the plan properly. The optimizer may misestimate cardinalities for a variety of reasons, such as missing or inaccurate statistics, or complex predicates. Whatever the reason for the misestimate, cardinality feedback may be able to help.

You notice a performance change in your production Oracle 12c database. You want to know which change caused this performance difference. Which method or feature should you use?

Correct Answer:A

An application accesses a small lookup table frequently. You notice that the required data blocks are getting aged out of the default buffer cache.
How would you guarantee that the blocks for the table never age out?

Correct Answer:A
Schema objects are referenced with varying usage patterns; therefore, their cache behavior may be quite different. Multiple buffer pools enable you to address these differences. You can use a KEEP buffer pool to maintain objects in the buffer cache and a RECYCLE buffer pool to prevent objects from consuming unnecessary space in the cache. When an object is allocated to a cache, all blocks from that object are placed in that cache. Oracle maintains a DEFAULT buffer pool for objects that have not been assigned to one of the buffer pools.