Oracle 1z0-066 Oracle Database 12c: Data Guard Administrator Exam Practice Test

The route between fs1 and physical standbase in the remote region, like physt2, should be SYNC or SYNC NOAFFIRM.

Note:

Fast Sync is a new Data Guard capability available with Oracle Database 12c. Fast Sync enables use of the destination parameter NOAFFIRM which specifies that the standby acknowledge receipt of redo without waiting for the write to the standby redo log file to complete. Fast Sync can improve application response time in a SYNC configuration by removing remote I/O from the total round trip time.

Active Data Guard Far Sync Architecture

To reinstate the failed primary database, start it to the mounted state. Then run DGMGRL, connect to the new primary database and reinstate the old primary database.

References: https://docs.oracle.com/cd/B28359_01/server.111/b28295/cli.htm

E: SHOW FAST_START FAILOVER

Displays all fast-start failover related information.

F: SHOW DATABASE

Displays information about the specified database.

References:

Use Data Guard Redo Apply Best Practices

To improve the Redo Apply rate of a physical standby database (and media recovery):

* Set DB_CACHE_SIZE to a Value Greater than on the Primary Database

* Set DB_BLOCK_CHECKSUM=FULL and DB_BLOCK_CHECKING=MEDIUM or FULL

* Maximize I/O Rates on Standby Redo Logs and Archived Redo Logs

* Assess Recovery Rate

* Assess Database Wait Events

* Tune I/O Operations

* Assess System Resources

References: https://docs.oracle.com/database/121/HABPT/config_dg.htm#HABPT4904

E: A snapshot standby database receives and archives, but does not apply, redo data from a primary database.

D: Snapshot standby databases are best used in scenarios where the benefit of having a temporary, updatable snapshot of the primary database justifies additional administrative complexity and increased time to recover from primary database failures.

Note: Redo data received from the primary database is applied when a snapshot standby database is converted back into a physical standby database, after discarding all local updates to the snapshot standby database.

The data in the primary database is fully protected however, because a snapshot standby can be converted back into a physical standby database at any time, and the redo data received from the primary will then be applied.

There are three parameters that can be modified to control the number of processes allocated to SQL Apply: MAX_SERVERS, APPLY_SERVERS, and PREPARE_SERVERS. The following relationships must always hold true:

APPLY_SERVERS + PREPARE_SERVERS = MAX_SERVERS - 3

This is because SQL Apply always allocates one process for the READER, BUILDER, and ANALYZER roles.

References: https://docs.oracle.com/cd/B28359_01/server.111/b28294/manage_ls.htm

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 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

References:

A: SQL Apply converts the data from the archived redo log or standby redo log in to SQL statements and then executes these SQL statements on the logical standby database.

Note: Log apply services use the following methods to maintain physical and logical standby databases:

* Redo apply (physical standby databases only)

* SQL Apply (logical standby databases only)

E: Standby redo log files are required to use real-time apply.

By default, the redo data is applied from archived redo log files. When performing Redo Apply, a physical standby database can use the real-time apply feature to apply redo directly from the standby redo log files as they are being written by the RFS process.

Applying Redo Data to Physical Standby Databases

C: The archiver (ARCn) process or the log writer (LGWR) process on the primary database can transmit redo data directly to remote standby redo log files, potentially eliminating the need to register a partial archived log file (for example, to recover after a standby database crashes).

References:

B: The Data Guard monitor process (DMON) is an Oracle background process that runs for every database instance that is managed by the broker. When you start the Data Guard broker, a DMON process is created.

C: The following list describes some of the operations the broker automates and simplifies:

* Invoking switchover or failover with a single command to initiate and control complex role changes across all databases in the configuration.

Etc.

A: DB_NAME

On a primary database, specify the name used when the database was created. On a physical standby database, use the DB_NAME of the primary database.

C: Ensure the COMPATIBLE initialization parameter is set to the same value on both the primary and standby databases. If the values differ, redo transport services may be unable to transmit redo data from the primary database to the standby databases.

D: DB_FILE_NAME_CONVERT

Specify the path name and filename location of the primary database data files followed by the standby location. This parameter converts the path names of the primary database data files to the standby data file path names.

E: DB_UNIQUE_NAME

Specify a unique name for each database. This name stays with the database and does not change, even if the primary and standby databases reverse roles.

F: FAL_SERVER

Specify the Oracle Net service name of the FAL server (typically this is the database running in the primary role).

References:

C: Prerequisites that must be met before the broker allows you to enable fast-start failover include: Enable Flashback Database and set up a fast recovery area on both the primary database and the target standby database.

E: Introduced in 11g, snapshot standby allows the standby database to be opened in read-write mode. When switched back into standby mode, all changes made whilst in read-write mode are lost. This is achieved using flashback database, but the standby database does not need to have flashback database explicitly enabled to take advantage of this feature, thought it works just the same if it is.

References: https://docs.oracle.com/database/121/DGBKR/sofo.htm#DGBKR391

https://oracle-base.com/articles/12c/data-guard-setup-using-broker-12cr1#flashback_database

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.