Which three must he true for Smart Scans to be done?
A.
Executing a query in parallel
B.
Setting _serial_direct_read=true in the session issuing the SQL statements
C.
Having direct path reads used at run time
D.
Having a 4 megAUsize for the ASM diskgroup containing the tablespace in which tables
accessed by a query are stored
E.
Cell_offload_process = true for the ASM diskgroup containing the tablespace in which tables
accessed by a query are stored.
F.
cell.smart_scan_capable=true for the ASM diskgroup containing the tablespace in which tables
accessed by a query are stored.
Explanation:
F:ASM Diskgroup has an attribute: cell.smart_scan_capable
• Must be set to TRUE for Smart Scans to work
Smart Scans do not need to be run in parallel so A is incorrect. C, E, and F should be the answer.
cell_offload_process is a database parameter not ASM. So B, C and F should be the answer.
Exadata Smart Scan FAQ (Doc ID 1927934.1)
if B is correct then A too.I think C,E,F are the correct answers
C F are 100% correct
E is 100% incorrect
A, C, F are correct answer.
Ref : Exadata Smart Scan FAQ (Doc ID 1927934.1)
This note also mentions that option E is correct.
A. is INCORRECT because serially executed query can also use Smart Scans by setting _serial_direct_read_true
B. is INCORRECT because this is not MUST to use _serial_direct_read=true because parallel queries can use Smart Scans without setting this parameter
C. is CORRECT because it actually encompasses option A and B above.
D. is INCORRECT as this is not the requirement for Smart Scan
E. is CORRECT
F. is CORRECT
The CELL_OFFLOAD_PROCESSING initialization parameter enables or disables Smart Scan.
Not Cell_offload_process
So E is wrong
_serial_direct_read=TRUE can be used to force direct path reads, so B is correct
Agree with eleoracle , B C F
The answers A & B looks correct in the following context:
Direct-path reads are automatically used for parallel queries
Direct-path reads may be used for serial queries:
Use _serial_direct_read=TRUE to force direct path reads
A is wrong. query not in parallel can do smart scan
B is right. _serial_direct_read=true can force queries not run in parallel to do direct path read, thus smart scan.
C is right. direct path read will do smart scan
D is wrong. 4MB AU won’t trigger smart scan
E is wrong. cell_offload_processing is a DB parameter
F is right. ASM diskgroup attribute cell.smart_scan_capable has to be true for smart scan
So B.C.F. are correct
A. is INCORRECT because serially executed query can also use Smart Scans by setting _serial_direct_read_true
B. is INCORRECT because this is not MUST to use _serial_direct_read=true because parallel queries can use Smart Scans without setting this parameter
C. is CORRECT because it actually encompasses option A and B above.
D. is INCORRECT as this is not the requirement for Smart Scan
E. is CORRECT
F. is CORRECT