1Z0-006 Oracle Database Architecture 4 — Questions and Answers
Question 1: What is an extent in Oracle's logical storage hierarchy?
- A single Oracle data block
- A contiguous set of Oracle data blocks (Correct answer)
- A named collection of segments
- A memory allocation in the SGA
Correct answer: A contiguous set of Oracle data blocks
An extent is a specific number of contiguous Oracle data blocks allocated at once to a segment when it needs to grow.
Question 2: Which component of the shared pool stores the Oracle data dictionary cache (row cache)?
- Library cache
- Dictionary cache (Correct answer)
- Buffer cache
- Result cache
Correct answer: Dictionary cache
The dictionary cache (also called the row cache) within the shared pool stores frequently accessed data dictionary information to avoid repeated disk reads.
Question 3: In a dedicated server configuration, how many server processes handle a single user session?
- One shared server process handles all sessions
- One dedicated server process per session (Correct answer)
- One background process per session
- Multiple DBWR processes per session
Correct answer: One dedicated server process per session
In dedicated server mode, Oracle spawns one dedicated server process exclusively for each user session for its entire duration.
Question 4: What is the System Change Number (SCN) used for in Oracle?
- Tracking the number of active sessions
- Providing a consistent ordering of database changes for recovery and read consistency (Correct answer)
- Measuring SGA memory consumption
- Identifying the current LGWR write cycle
Correct answer: Providing a consistent ordering of database changes for recovery and read consistency
The SCN is Oracle's internal timestamp that uniquely orders database changes, enabling consistent reads and precise point-in-time recovery.
Question 5: Which Oracle background process performs instance recovery automatically when the database is restarted after a crash?
- PMON
- DBWn
- SMON (Correct answer)
- ARCn
Correct answer: SMON
SMON (System Monitor) performs instance recovery at startup by rolling forward committed changes from redo logs and rolling back uncommitted transactions.
Question 6: What does multiplexing the control file mean in Oracle?
- Encrypting the control file for security
- Keeping multiple identical copies of the control file in different locations (Correct answer)
- Compressing the control file to save space
- Splitting the control file across multiple tablespaces
Correct answer: Keeping multiple identical copies of the control file in different locations
Multiplexing the control file means maintaining two or more identical copies on separate disk locations so that no single disk failure can destroy all copies.
Question 7: What is the smallest unit of I/O in the Oracle database storage architecture?
- An extent
- A segment
- An Oracle data block (Correct answer)
- A tablespace
Correct answer: An Oracle data block
The Oracle data block is the smallest unit of storage that Oracle reads from and writes to disk, and its size is set at database creation.
1Z0-006 Oracle Database Architecture 4
What is an extent in Oracle's logical storage hierarchy?