Which three statements are true about snapshot standby databases?
A.
Snapshot standby databases may be used for rolling release upgrades.
B.
If datafiles grow while a database is a snapshot standby database, then they shrink when converted back to a physical standby database.
C.
Flashback logs are used to convert a snapshot standby database back into a physical standby database.
D.
A snapshot standby database can have Real-Time Query enabled.
E.
A guaranteed restore point is created automatically when a physical standby database is converted into a snapshot standby database.
Explanation:
C: Flashback Database is similar to conventional point-in-time recovery in its effects. It enables you to return a database to its state at a time in the recent past.
Flashback Database uses its own logging mechanism, creating flashback logs and storing them in the fast recovery area. You can only use Flashback Database if
flashback logs are available. Flashback Database is used to convert a snapshot standby database back into a physical standby database.
E: When we convert the physical standby database to snapshot standby database a guaranteed restore point is created. This guaranteed restore point is used to
flashback a snapshot standby database to its original state.
Incorrect Answers:
A: Oracle Database supports the installation of database software upgrades, and the application of patch sets, in a rolling fashion—with near zero database
downtime—by using Data Guard SQL Apply and logical standby databases.https://docs.oracle.com/cd/E11882_01/server.112/e41134/manage_ps.htm#SBYDB4803
http://satya-dba.blogspot.se/2012/06/snapshot-standby-databases-oracle.html
only 2 correct answers!
The question is incorrect, there are only 2 correct answers and not 3.
These are C and E, as given.
A and D are incorrect. When the snapshot is initiated, the standby DB is writable and can be considered a different DB from the primary – until it is flashed back and arch redo applied. Real time query and rolling upgrades would require the standby to be in sync with primary.
B is incorrect. When converted back into a physical standby database, the entire DB is rolled back to be identical to the primary. A physical standby is a block-for-block copy of the primary DB and any backup taken of a datafile on the standby is a valid backup for restore on primary – therefore the datafiles must be identical!
C is correct. The DB must be put back into a state where archive logs can be applied. Flashback is the best and easiest way to do this, so is what Oracle uses.
E is correct. Creating a GRP is the easiest automatable way to allow flashback to the instant the standby was created.
Correct A,C,E
‘A’ is correct as there is nothing against converting back snapshot standby database to physical standby, wait to get in sync with primary and then use the same for rolling release upgrade.
PeraDetlic, if you are in rigth,
following the docs steps
snap -> physical (sync redo)
physical -> logical
logical ->rolling release upgrade
i think you should pay attention in exam question about the request is two or three alternatives.
thanks
B is true. So for me answers are B,C,E
I did some tests
DGMGRL> show configuration;
Configuration – ORCL_DR
Protection Mode: MaxPerformance
Members:
ORCL_SITE – Primary database
ORCL_SITE1 – Physical standby database
ORCL_SITE2 – Snapshot standby database
ORCL_SITE3 – Logical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS (status updated 37 seconds ago)
The size of datafile user01 in ORCL_SITE2
SQL> select sum(bytes)/1024/1024 from v$datafile;
SUM(BYTES)/1024/1024
——————–
1455
############# I insert some data so to increase the datafile size ############
SQL> create table test(nom varchar2(100)) tablespace users;
Table created.
SQL> insert into test values (‘teeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeefdfgeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee’);
1 row created.
SQL> insert into test select * from test;
1 row created.
SQL> insert into test select * from test;
2 rows created.
SQL> insert into test select * from test;
512 rows created.
….
….
SQL> insert into test select * from test;
524288 rows created.
SQL> commit;
Commit complete.
SQL> select sum(bytes)/1024/1024 from v$datafile;
SUM(BYTES)/1024/1024
——————–
1571.25
############# when convert back to physical standby the file was srinked to it’s initial sze ######################
SQL> select sum(bytes)/1024/1024 from v$datafile;
SUM(BYTES)/1024/1024
——————–
1455
Thanks
I tried option B too and It’s correct
Answer: B, C and E