1Z0-006 Oracle Database Architecture 3 — Questions and Answers
Question 1: Which SGA component is allocated per-server and stores session-specific data such as sort areas and cursor state?
- System Global Area (SGA)
- Program Global Area (PGA) (Correct answer)
- Shared pool
- Redo log buffer
Correct answer: Program Global Area (PGA)
The PGA (Program Global Area) is private memory allocated for each server process, storing session-specific data like sort work areas and bind variable values.
Question 2: What happens to the redo log buffer entries when it is one-third full or a COMMIT is issued?
- DBWn writes them to data files
- LGWR writes them to the redo log files (Correct answer)
- CKPT updates the control file
- SMON merges them into the shared pool
Correct answer: LGWR writes them to the redo log files
LGWR writes redo log buffer contents to the online redo log files when triggered by a COMMIT, when the buffer is one-third full, or every three seconds.
Question 3: Which Oracle startup mode allows the DBA to perform maintenance but prevents regular users from connecting?
- NOMOUNT
- MOUNT
- OPEN RESTRICTED (Correct answer)
- OPEN READ ONLY
Correct answer: OPEN RESTRICTED
OPEN RESTRICTED mode opens the database but limits access to users with the RESTRICTED SESSION privilege, allowing DBA maintenance tasks.
Question 4: What is the function of the CKPT (Checkpoint) process?
- Archiving online redo logs to a remote location
- Updating data file headers and the control file with the latest checkpoint SCN (Correct answer)
- Reading data blocks from disk into the buffer cache
- Rolling back uncommitted transactions at startup
Correct answer: Updating data file headers and the control file with the latest checkpoint SCN
CKPT updates the headers of data files and the control file with the current checkpoint System Change Number (SCN) after a checkpoint event.
Question 5: In Oracle architecture, what is a segment?
- A portion of the SGA reserved for SQL parsing
- A set of extents that store a specific type of database object (Correct answer)
- A single Oracle background process
- A named group of redo log files
Correct answer: A set of extents that store a specific type of database object
A segment is a set of extents allocated for a specific database object such as a table, index, or undo data within a tablespace.
Question 6: Which file must Oracle open during the MOUNT startup stage before the database can be fully opened?
- Data files
- Redo log files
- Control file (Correct answer)
- Parameter file (SPFILE)
Correct answer: Control file
During the MOUNT stage, Oracle opens the control file to read the locations and names of all data files and redo log files.
Question 7: What is the purpose of the ARCn (Archiver) background process?
- Compressing data blocks to save disk space
- Copying filled online redo log groups to archive log destinations (Correct answer)
- Rebuilding corrupted data file blocks
- Merging temporary segments after sorts complete
Correct answer: Copying filled online redo log groups to archive log destinations
ARCn automatically copies filled online redo log files to archive log destinations when the database is in ARCHIVELOG mode.
1Z0-006 Oracle Database Architecture 3
Which SGA component is allocated per-server and stores session-specific data such as sort areas and cursor state?