Oracle 21c - Far Sync Instance - Result Cache - Prepare Database for DG - Data Guard New Features - Explored!
Hello All,
21c New Feature – Data Guard Broker Create Far Sync Instance
A new feature in Oracle 21c is the ability to create a Data Guard Far Sync Instance via Data Guard Broker.
The DGMGRL command CREATE FAR_SYNC automates the entire process of creating the Far Sync database instance for a Data Guard Configuration.
It internally runs the RMAN DUPLICATE TARGET DATABASE FOR FARSYNC command and creates the Far Sync instance with the appropriate parameters.
Oracle 21c New Feature – Prepare Database For Data Guard
The Data Guard Broker PREPARE DATABASE FOR DATA GUARD command configures a database to be used as a Primary Database in a Data Guard Broker configuration.
It enables and sets a number of database parameters like LOG_BUFFER, DG_BROKER_START, STANDBY_FILE_MANAGEMENT, DB_BLOCK_CHECKSUM etc.
It also enables FLASHBACK and ARCHIVELOG for the database and creates the Standby Redo Log files if they do not exist.
In addition, it enables FORCE LOGGING for the database and configures the RMAN property for archivelog deletion to SHIPPED TO ALL STANDBY.
DGMGRL>PREPARE DATABASE FOR DATA GUARD WITH DB_UNIQUE_NAME IS dg1 DB_RECOVERY_FILE_DEST IS "+RECO" DB_RECOVERY_FILE_DEST_SIZE is "20G";
Preparing database "dg1" for Data Guard.
Initialization parameter LOG_BUFFER set to 268435456.
Primary database must be restarted after setting static initialization parameters.
Primary database must be restarted to enable archivelog mode.
Shutting down database "dg1".
Database closed.
Database dismounted.
ORACLE instance shut down.
Starting database "dg1" to mounted mode.
ORACLE instance started.
Database mounted.
Initialization parameter DB_FLASHBACK_RETENTION_TARGET set to 120.
Initialization parameter PARALLEL_THREADS_PER_CPU set to 1.
RMAN configuration archivelog deletion policy set to SHIPPED TO ALL STANDBY.
Initialization parameter DB_RECOVERY_FILE_DEST_SIZE set to '20G'.
Initialization parameter DB_RECOVERY_FILE_DEST set to '+RECO'.
LOG_ARCHIVE_DEST_n initialization parameter already set for local archival.
Initialization parameter LOG_ARCHIVE_DEST_2 set to 'location=use_db_recovery_file_dest valid_for=(all_logfiles, all_roles)'.
Initialization parameter LOG_ARCHIVE_DEST_STATE_2 set to 'Enable'.
Adding standby log group size 1073741824 and assigning it to thread 1.
Adding standby log group size 1073741824 and assigning it to thread 1.
Adding standby log group size 1073741824 and assigning it to thread 1.
Initialization parameter STANDBY_FILE_MANAGEMENT set to 'AUTO'.
Initialization parameter DG_BROKER_START set to TRUE.
Database set to FORCE LOGGING.
Database set to ARCHIVELOG.
Database set to FLASHBACK ON.
Database opened.
21c New Feature – Result Cache For Standby Database
Oracle 21c introduces the ability to improve the performance of queries executed on the read-only active Standby Database by enabling the use of the Result Cache feature to store query results for recurring use- so not just enabled on the Primary database, but the Standby database as well.
The new Oracle 21c clause RESULT_CACHE (STANDBY ENABLE) can be used as part of both CREATE as well as ALTER TABLE statements.
Enable the Result Cache for ADG Standby Database
SQL> alter table demo.tab1 RESULT_CACHE (STANDBY ENABLE);
21c New Feature – Attention Log
Another new feature in Oracle 21c is the attention.log file.
The database alert.log contains lots of information – but a lot of the content of the alert log is just “informational” in nature.
Very often the DBA needs to process or interpret only information which requires his urgent attention.
Rather than have to scroll through many lines of the alert log to obtain information about critical database events, the DBA can now just view the single attention.log file.
So no more having to use things like sed, grep,awk to filter the alert log!
Messages in the attention log are classified by attention type like Error, Warning, Notification, or Additional information.
Messages are further classified even by urgency – like Immediate, Soon or Deferrable.
The file is also available in XML and JSON format.
Cheers!
Ramesh.
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