-
web.groovymark@gmail.com
- December 5, 2024
Question 01
Which of the following statements regarding Oracle Database control files is true?
A) A database can have only one control file.
B) A database must have at least two control files.
C) A database may have zero or more control files.
D) A database must have at least one control file.
Correct Answer: D) A database must have at least one control file.
Explanation: The control file is one of the most critical files in an Oracle database. It contains information required to maintain and recover the database, such as the database name, timestamps of database creation, and the location of data files and redo log files. An Oracle database must have at least one control file to start and run the database.
Question 02
Which component is configured at database startup and cannot be dynamically managed?
A) Redo log buffer
B) Streams pool
C) Java pool
D) Shared pool
E) None of the above
Correct Answer: A) Redo log buffer
Explanation: The redo log buffer is set at instance startup and is not dynamically alterable without restarting the instance.
Question 03
Which component is not part of an Oracle instance?
A) System global area
B) Process monitor
C) Control file
D) Shared pool
E) None
Correct Answer: C) Control file
Explanation: The control file, data file, and redo log files are part of the Oracle database, not the Oracle instance.
Question 04
Which background process guarantees that committed data is saved even when the changes have not been recorded in data files?
A) DBWn
B) PMON
C) LGWR
D) CKPT
E) ARCn
Correct Answer: C) LGWR
Explanation: The log writer (LGWR) process writes the redo log buffer information to the online redo log files.
Question 05
User John has updated several rows in a table and issued a commit. What does the DBWn (database writer) process do at this time in response to the commit event?
A) Writes the changed blocks to data files.
B) Writes the changed blocks to redo log files.
C) Triggers checkpoint and thus LGWR writes the changes to redo log files.
D) Does nothing.
Correct Answer: D) Does nothing.
Explanation: Database writer takes no action against the commit event. LGWR handles the commit.
Question 06
Which of the following best describes a RAC configuration?
A) One database, multiple instances
B) One instance, multiple databases
C) Multiple databases plugged in from multiple servers
D) Multiple databases, multiple instances
Correct Answer: A) One database, multiple instances
Explanation: With Real Application Clusters, multiple instances (nodes) can mount one database.
Question 07
Which component of the SGA contains the parsed SQL code?
A) Database buffer cache
B) Dictionary cache
C) Library cache
D) Parse cache
Correct Answer: C) Library cache
Explanation: The shared SQL area is stored in the library cache in a shared pool and is shared between users.
Question 08
Which tasks are accomplished by the SMON process? (Choose all that apply.)
A) Performs recovery at instance startup
B) Performs cleanup after a user session is terminated
C) Starts any server process that stopped running
D) Coalesces contiguous free space in dictionary-managed tablespaces
Correct Answer: A, D) Performs recovery at instance startup; Coalesces contiguous free space in dictionary-managed tablespaces.
Explanation: SMON is responsible for performing instance recovery using the online redo log files and for coalescing contiguous free space in tablespaces.
Question 09
Choose the best statement from the options related to segments.
A) A contiguous set of blocks constitutes a segment.
B) A nonpartitioned table can have only one segment.
C) A segment can belong to more than one tablespace.
D) All of the above are true.
Correct Answer: B) A nonpartitioned table can have only one segment.
Explanation: A table or index has a segment. A segment consists of one or more extents. A segment can belong to only one tablespace.
Question 10
From the following list, choose two processes that are optional in an Oracle Database 12c database.
A) MMON
B) MMNL
C) ARCn
D) MMAN
Correct Answer: C, D) ARCn; MMAN
Explanation: The ARCn (Archiver) process is optional and is enabled only when the database is running in ARCHIVELOG mode. MMAN (Memory Manager) is active only when Automatic Memory operations are configured.
Question 11
Which SGA component will you increase or configure so that RMAN tape backups do not use memory from the shared pool?
A) Java pool
B) Streams pool
C) Recovery pool
D) Large pool
Correct Answer: D) Large pool
Explanation: The large pool is configured so that RMAN does not use the shared pool.
Question 12
When a user session is terminated, which processes are responsible for cleaning up and releasing locks? (Choose all that apply.)
A) DBWn
B) LGWR
C) MMON
D) PMON
E) SMON
Correct Answer: D) PMON
Explanation: PMON is responsible for cleaning up failed user processes and releasing locks.
Question 13
The LRU algorithm is used to manage what part of the Oracle architecture
A) Users who log on to the database infrequently and may be candidates for being dropped
B) The data file that stores the least amount of information and will need the least frequent backup
C) The tables that users rarely access so that they can be moved to a less active tablespace
D) The shared pool and database buffer cache portions of the SGA
Correct Answer: D) The shared pool and database buffer cache portions of the SGA.
Explanation: The LRU mechanism ensures that frequently used objects remain cached in memory.
Question 14
Two structures make up an Oracle server: an instance and a database. Which of the following best describes the difference between an Oracle instance and a database?
A) An instance consists of memory structures and processes, whereas a database is composed of physical files.
B) An instance is used only during database creation; after that, the database is all that is needed.
C) An instance is started whenever the demands on the database are high, but the database is used all the time.
D) An instance is configured using a pfile, whereas a database is configured using a spfile.
Correct Answer: A) An instance consists of memory structures and processes, whereas a database is composed of physical files.
Explanation: The instance consists of the SGA and background processes; the database is made up of physical files.
Question 15
Which of the following is the proper order of Oracle’s storage hierarchy, from smallest to largest?
A) Operating-system block, database block, segment, extent
B) Operating-system block, database block, extent, segment
C) Segment, extent, database block, operating-system block
D) Segment, database block, extent, operating-system block
Correct Answer: B) Operating-system block, database block, extent, segment.
Explanation: Multiple operating-system blocks make up database blocks, which make up extents, which make up segments.
Question 16
The DBA unknowingly terminated the process ID belonging to the PMON process of Oracle Database 12c database using the kill -9 command on Unix. Choose the best answer.
A) Oracle spawns another PMON process automatically.
B) The database hangs, and the DBA must manually start a PMON process.
C) If the database is in ARCHIVELOG mode, Oracle automatically starts another PMON process and recovers from the database hang.
D) The instance crashes and needs to be restarted.
Correct Answer: D) The instance crashes and needs to be restarted.
Explanation: PMON is critical; terminating it will crash the database.
Question 17
When an incremental checkpoint happens in a database, which file(s) are updated with the checkpoint position? Choose all options that are correct.
A) Data files
B) Control files
C) Initialization Parameter Files
D) Redo log files
E) Archive log files
Correct Answer: B) Control files.
Explanation: During an incremental checkpoint, the control file is updated with the checkpoint position.
Question 18
User Isabella updates a table and commits the change after a few seconds. Which of the following actions are happening in the database? Order them in the correct sequence and ignore the actions that are not relevant.
A) Oracle reads the blocks from data file to buffer cache and updates the blocks.
B) Changed blocks from the buffer cache are written to data files.
C) The user commits the change.
D) LGWR writes the changed blocks to the redo log buffer.
E) The server process writes the change vectors to the redo log buffer.
F) LGWR flushes the redo log buffer to redo log files.
G) A checkpoint occurs.
Correct Answer: A, E, C, F, G, B) Oracle reads the blocks from data file to buffer cache and updates the blocks; The server process writes the change vectors to the redo log buffer; The user commits the change; LGWR flushes the redo log buffer to redo log files; A checkpoint occurs; Changed blocks from the buffer cache are written to data files.
Explanation: Data blocks are changed in memory, then the redo log buffers are written to redo log files on commit.
Question 19
Querying the V$LOG file shows the following information. Which redo group files are required for instance crash recovery?
1 NO CURRENT
2 NO INACTIVE
3 NO INACTIVE
4 NO ACTIVE
A) Group 1 and 4
B) Group 2 and 3
C) Groups 1 through 4
D) Group 1
E) Group 4
Correct Answer: A) Group 1 and 4
Explanation: Redo log groups with status CURRENT and ACTIVE are required during instance crash recovery.
Question 20
You noticed that the current value of the UNDO_RETENTION parameter is 900 and is too low for some of your transactions. The database was created using DBCA. You issue the following statement: ALTER SYSTEM SET UNDO_RETENTION=4800; Which option is true?
A) UNDO_RETENTION is a static parameter and, therefore, cannot be changed using ALTER SYSTEM.
B) The change will be available to the instance only after a database cycle.
C) The value is changed in memory, and when the database restarts the next time, the new value will be preserved when using the spfile.
D) The value is changed only in memory, and the server parameter file needs to be updated for the change to persist across database shutdowns.
Correct Answer: C) The value is changed in memory, and when the database restarts the next time, the new value will be preserved when using the spfile.
Explanation: When using ALTER SYSTEM to change parameter values, the change is made to the server parameter file (spfile) too, because the default for the SCOPE clause is BOTH.
