1Z0-006 Oracle Database Architecture 2 — Questions and Answers
Question 1: Which SGA component stores the most recently executed SQL statements and their execution plans?
- Database buffer cache
- Shared pool (Correct answer)
- Redo log buffer
- Large pool
Correct answer: Shared pool
The shared pool contains the library cache, which stores parsed SQL statements and execution plans for reuse.
Question 2: What is the primary role of the PMON (Process Monitor) background process?
- Writing dirty buffers to data files
- Cleaning up after failed user processes (Correct answer)
- Archiving filled redo log groups
- Updating control files with checkpoint info
Correct answer: Cleaning up after failed user processes
PMON detects failed user processes and cleans up the cache and releases resources such as locks that the failed process held.
Question 3: In Oracle, which type of file records all changes made to the database and is critical for instance recovery?
- Data files
- Control files
- Redo log files (Correct answer)
- Archive log files
Correct answer: Redo log files
Redo log files record all changes (redo entries) to the database and are used to recover committed transactions after a failure.
Question 4: What does the term 'Oracle instance' specifically refer to?
- The set of physical files on disk
- The combination of SGA and background processes (Correct answer)
- The user schemas and their objects
- The tablespaces and their data files
Correct answer: The combination of SGA and background processes
An Oracle instance is defined as the combination of the System Global Area (SGA) memory structure and the Oracle background processes.
Question 5: Which background process is responsible for writing modified data blocks from the buffer cache to the data files?
- LGWR
- CKPT
- SMON
- DBWn (Correct answer)
Correct answer: DBWn
DBWn (Database Writer) writes dirty (modified) buffers from the database buffer cache to the data files on disk.
Question 6: A tablespace in Oracle is best described as which type of structure?
- A physical file on disk
- A logical storage container made up of one or more data files (Correct answer)
- A memory area within the SGA
- A background process group
Correct answer: A logical storage container made up of one or more data files
A tablespace is a logical storage unit in Oracle that corresponds physically to one or more data files on the operating system.
Question 7: Which Oracle memory structure temporarily stores transaction undo information to support read consistency and rollback?
- Redo log buffer
- Undo tablespace segments (Correct answer)
- Shared pool
- Java pool
Correct answer: Undo tablespace segments
Undo segments (stored in the undo tablespace) hold before-images of changed data to support rollback operations and read-consistent queries.
1Z0-006 Oracle Database Architecture 2
Which SGA component stores the most recently executed SQL statements and their execution plans?