Which four factors can influence the rate of SQL apply on a logical standby database?

• A.the size of the undo tablespace on the logical standby database
• B.the number of full table scans performed by SQL apply
• C.the number of coordinator processes on the standby database instance
• D.the size of the shared pool
• E.the number of APPLIER processes
• F.the number of PREPARER processes

Correct Answer: B,D,E,F

Explanation/Reference:
B: If a table still does not have any unique index specified on the logical standby database, this may cause UPDATE statements to do full table scans on the logical standby database. You can remedy that by adding a unique index on the a column on the logical standby database.
E: SQL Apply uses a collection of background processes to apply changes from the primary database to the logical standby database.
During apply processing:
* The ANALYZER process identifies dependencies between different transactions.
* The COORDINATOR process (LSP) assigns transactions to different appliers and coordinates among them to ensure that dependencies between transactions are honored.
* The APPLIER processes applies transactions to the logical standby database under the supervision of the coordinator process.
F: The PREPARER process is used during the log mining process, which is part of the SQL apply process.
D: The Shared Pool is used by the preparar and Builder proccesses.
Figure: SQL Apply Processing

Incorrect Answers:
C: There is only one coordinator process.
References: https://docs.oracle.com/cd/B28359_01/server.111/b28294/manage_ls.htm

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Which three statements are true about Global Sequences when connected to a physical standby database with Real-Time Query enabled?

• A.If the CACHE option is set then the size of the cache must be at least 100.
• B.Their creation requires that a LOG_ARCHIVE_DEST_n parameter be defined in the standby that points back to their primary.
• C.Their usage will always have a performance impact on the primary database.
• D.Their usage may have a performance impact on the physical standby database if the CACHE size is too small
• E.They must have the NOORDER and CACHE options set.

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Attempting to start the observer raises an error:
DGMGRL> start observer:
DGM-16954: Unable to open and lock the Observer configuration file Failed.
Identify two possible reasons for this error.

• A.Fast-Start Failover is not yet enabled for this Data Guard configuration.
• B.The observer configuration file is marked read-only.
• C.There is already an observer running for this Data Guard configuration.
• D.There is another observer running for a Data Guard configuration which uses the same observer configuration file.
• E.The broker configuration has not yet been created.

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Examine the Data Guard configuration:
DGMGRL> show configuration;
Configuration ‒ Animals
Protection Mode: MaxAvailability
Databases:
dogs ‒ Primary database
dogsfs1 ‒ Far Sync
sheep ‒ Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS
An attempt to enable fast-start failover raises an error:
DGMGRL> enable fast_start failover;
Error: ORA-16693: requirements not met for enabling fast-start failover Failed.
Identify two possible reasons for this error. (Choose two.)

• A.The FastStartFailoverTarget property is not set on Sheep.
• B.The FastStartFailoverTarget property is not set on Dogs.
• C.The FastStartFailoverTarget property is not set on DogsFS1.
• D.The LogXptMode property is set to ASYNC on Dogs.
• E.The RedoRoutes property is not set on Dogs.
• F.The RedoRoutes property is not set on DogsFS1.

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Attempting to start the observer raises an error
DGMGRL> start observer:
DGM-16954 Unable to open and lock the Observer configuration file Failed.
Identify two possible ways to start the observer successfully

• A.start the observer in a different working directory.
• B.Set the Observer Override property to TRUE before starting the observer
• C.Enable Fast-Start Failover before starting the observer
• D.Start the observer using a different observer configuration file.
• E.Create a broker configuration and enable Fast-Start Failover before starting the observer

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