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?（）

多项选择题Which three features work together, to allow a SQL statement to have different cursors for the samestatement based on different selectivity ranges?（）

A. Bind Variable Peeking
B. SQL Plan Baselines
C. Adaptive Cursor Sharing
D. Bind variable used in a SQL statement
E. Literals in a SQL statement

多项选择题You notice a high number of waits for the db file scattered read and db file sequential read events in the recent Automatic Database Diagnostic Monitor (ADDM) report. After further investigation, you find that queries are performing too many full table scans and indexes are not being used even though the filter columns are indexed. Identify three possible reasons for this.（）

A. Missing or stale histogram statistics
B. Undersized shared pool
C. High clustering factor for the indexes
D. High value for the DB_FILE_MULTIBLOCK_READ_COUNT parameter
E. Oversized buffer cache

单项选择题Which statement is true concerning dropping a pluggable database (PDB)?（）

A. The PDB must be open in read-only mode.
B. The PDB must be in mount state.
C. The PDB must be unplugged.
D. The PDB data files are always removed from disk.
E. A dropped PDB can never be plugged back into a multitenant container database (CDB).

多项选择题You upgrade your Oracle database in a multiprocessor environment. As a recommended you execute thefollowing script:SQL > @utlrp.sqlWhich two actions does the script perform?（）

A. Parallel compilation of only the stored PL/SQL code
B. Sequential recompilation of only the stored PL/SQL code
C. Parallel recompilation of any stored PL/SQL code
D. Sequential recompilation of any stored PL/SQL code
E. Parallel recompilation of Java code
F. Sequential recompilation of Java code

多项选择题Identify two correct statements about multitenant architectures.（）

A. Multitenant architecture can be deployed only in a Real Application Clusters (RAC) configuration.
B. Multiple pluggable databases (PDBs) share certain multitenant container database (CDB) resources.
C. Multiple CDBs share certain PDB resources.
D. Multiple non-RAC CDB instances can mount the same PDB as long as they are on the same server.
E. Patches are always applied at the CDB level.
F. A PDB can have a private undo tablespace.