ByJoel PerézSkant Gupta
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Before starting, if you want to read about how to build an Oracle Dataguard Configuration in Cloud, you can read here:
#1 Oracle Cloud (DBaaS): Oracle Data Guard in Database Cloud Service ( DBCS )
#2 Oracle Cloud (DBaaS): Switchover, Failover & Reinstate Operations on Oracle Data Guard using DBCS Console
#3 Oracle Cloud (DBaaS): Reinstating a Failed Primary Database using dbaascli utility ( Oracle Data Guard on Cloud )
#4 Oracle Cloud (DBaaS): Using dbaascli Utility for Switchover & Failover Operations on Oracle Data Guard
Now, Let's start to read..
Oracle Data Guard is an Oracle solution that seems will improve in a endless way. Every Oracle Release we have new features that perhaps we never expected to have.
Oracle 18c is not the exception, we have amazing new features, So.. Let's see..
New Broker VALIDATE commands
Personally, at the time to check or correct Oracle Data Guard configurations, one of the most common problems is the network configuration. Sometimes we are building RAC-RAC configurations with many servers.. many IPs.. etc.. and it's natural we can miss a name.. and IP.. etc.. at the end we can have some problems when this configuration is working and we have to start the tedious job to check every single detail.. ( Network Configuration.. Parameters.. etc.. ) to find where it's the problem.. With these 3 following commands we will be able to save a lot of time when we face that kind of difficulties..
VALIDATE DATABASE SPFILE
Validate parameters settings between the Primary and a Standby database.
VALIDATE NETWORK CONFIGURATION
Validate the network setup between all databases in the configuration
VALIDATE STATIC CONNECT IDENTIFIER
Verifies the static connect identifier setup in Single Instance databases the do not have Oracle Restart.
Multi-Instance Redo Apply
- Multi-Instance Redo Apply allows all standby nodes to participate in recovery
- In-memory DB (IMC) on Active Data Guard allows:
Creation of IMC tables and columns for analytics on Active Data Guard
Population with different data than production database
Offloading even more to your standby!
- IMC now works withMulti-Instance Redo Apply!
- Multi-Instance Redo apply also works with BCT
* Available only on Exadata and Oracle Cloud Offerings
18c: RMAN and Data Guard Enhancements
Active Data Guard Sync
New RECOVER STANDBY DATABASE FROM SERVICE
One command to refresh the standby database
Refreshes controlfile, datafile, restores newly added datafiles
Start RMAN and connect as target to the physical standby database.
Roll forward the physical standby database using the RECOVER STANDBY DATABASE command with the FROM SERVICE clause
RECOVER STANDBY DATABASE FROM SERVICE primary_db;
Creating GTTs on Active Data Guard
- Creating GTTs today will fail when executed on Active Data Guard
- In Oracle Database 18cCREATE GLOBAL TEMPORARY TABLEon an Active Data Guard standby will:
Create the GTT on the Primary
Wait for the GTT to be replicated and applied to the Active Data Guard standby
Return control to the user
Transient tables useful for reporting applications
Global temporary tables
Persistent, shared (global) table definition
Temporary, private (session-based) data content
Data physically exists for a transaction or session
Session-private statistics
Private temporary tables(18c)Temporary, private (session-based) table definition
Private table name and shape
Temporary, private (session-based) data content
Session or transaction duration
Executing DML on Active Data Guard
- DML Re-direction automatically performed from Active Data Guard standby to the Primary without compromising ACID
Standby ADG session waits for updates to show up on ADG via redo apply
DML data re-directed by an ADG session is only visible to that session before commit
DML data re-directed is visible to all sessions after ADG session commits
Enabled by setting parameter_enable_proxy_adg_redirect=TRUEand appropriate connectivity parameters
Respects ACID properties of a database for ADG session
Targeted for “Read MostlyOccasional Updates” applications
Keep Buffer Cache at Role Change
How often we did not dream for having a switchover without losing some transactions because of that..
Well, part of that dream "come true"..
- The database buffer cache state will be maintained on an ADG standby during a role change
- Automatic, nothing to set up.
Services need to be configured correctly
Control login attempts
- The ADG_ACCOUNT_INFO_TRACKING parameter extends the control of user account security information and reaction.
‘LOCAL’ (default value) continues to enforce the existing behavior
Maintains local copy of users account information in the Standby's in-memory view.
Login failures are only tracked locally on a per database basis and login denied when the failure maximum is reached.
- ‘GLOBAL’ triggers the new secure behavior
Maintains a single global copy of users account info across all Data Guard databases
Login failures across all databases in the Data Guard configuration count towards the maximum count and logins anywhere will be denied when the count is reached.
Data Guard and No Force Logging
How often you have been in the situation to repair/reinstate an Standby Database because a load was done in "No Logging mode".
It was really a hard situation for many companies to know that some specific loads could be done very efficient and fast in"No Logging mode" but sometimes there was not another option if we wanted to preserve the health state of our standby databases. Now, we have a new feature to make more versatile some specific loads in "No Logging mode"
Extended to provide better support in an Active Data Guard environment without significantly increasing the amount of redo generated.
Two new modes are added as alternatives to the existing nologging mode
Standby Nologging forLoad Performance
Ensures that standbys will receive the nonlogged data changes with the minimum impact to the speed of loading at the primary
The standby can transiently have nonlogged blocks. These nonlogged blocks will be automatically resolved by managed standby recovery.
Standby Nologging forData availability
Ensures all standbys have the data when the primary load commits but at the cost of throttling the speed of loading data at the primary
The standbys will never have any nonlogged blocks.
In Oracle Release 12.1 & 12.2 there a lot of new features that perhaps you have not experimented up to now. Here we have a list of all them so that you can differentiate to what release belongs the new features you will use.
RMAN
Oracle 18c: RMAN New Features.. What’s NEWS..
Review - Data Guard 12.1 New Features Summary
Data Guard
SYSDG Role for Data Guard specific operations
Multitenant Database Standbys
Default Real Time Apply
Transparent Online Data file movement
Single SQL*Plus Switchover command
No Primary instance shutdown for switchover
FastSync (SYNC NOAFFIRM)
Enhanced Extended Datatype Support for upgrades
Logical Standby support for additional data types
XMLType data for all storage models, Oracle Spatial, Oracle Multimedia, Oracle Text, Objects and Collections (including VARRAYs and nested collections), Database File System (DBFS), XDB, Oracle SecureFiles (deduplication), and User-defined types.
DBMS_SCHEDULER support for Rolling Upgrades
Broker VALIDATE DATABASE capability
Enhanced Broker configuring with RedoRoutes
Broker Resumable switchover
New Broker Observer properties and capabilities
Broker support of Cascading Redo destinations
Active Data Guard
Real Time Cascading Redo destinations
WAN Distance Zero Data Loss with Far Sync
Global Temporary Table DML on a standby
Sequences (global and session) on a standby
DBMS_ROLLING automated rolling upgrades
Support for Oracle Application Continuity
Support for Oracle Global Data Services
Review - Data Guard 12.2 New Features Summary
Data Guard
Use DBCA and EMCLI to create Standbys
Use RMAN and Enterprise Manager to create Far Sync Instances in addition to Standbys
Rest Interface to the Data Guard Broker
Chef tools to create and manage Data Guard standbys
Scripting with the Broker DGMGRLcommand line interface
Easily creating Subset Standby databases in Multitenant
Migrate and Failover PDBs with the Broker
Automatic Password File management
Easy repair of No Logging operations
Data File Block Comparison between Primary and Standby
Multiple FSFO Targetsand Observers
FSFO in Maximum Protection mode
Zero Data Loss Failovers in any mode with Storage Failures
Enhanced control of Alternate destinations
Convert to TDE easily with little or no downtime
Active Data Guard
Using all your Standby Instances to apply redo
Data Guard Broker Support and involvement in DBMS_ROLLING controlled rolling upgrades
Use the In Memory Column Store on your Standby
Use AWR and SQL Tuning Advisor to diagnose and tune Redo Apply and Query issues on your Active Data Guard Standby
Move users transparently during role change with Session Draining on the Primary and Preserving existing connections at the Active Data Guard Standby
More protection with Auto Block repair enhancements
this is the end of this article, we hope it can be useful.. Stay tune for more Oracle Database Cloud articles.
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Author Bios:
Joel Pérezis an Expert DBA ( Oracle ACE Director, Maximum Availability OCM, OCM Cloud Admin. & OCM12c/11g ) with over 17 years of Real World Experience in Oracle Technology, specialised in design and implement solutions of: High Availability, Disaster Recovery, Upgrades, Replication, Cloud and all area related to Oracle Databases. International consultant with duties, conferences & activities in more than 50 countries and countless clients around the world. Habitual and one of leading writers of Technical Oracle articles for: OTN Spanish, Portuguese, English and more. Regular Speaker in worldwide Oracle events like: OTN LAD (Latin America), OTN MENA (Middle East & Africa), OTN APAC ( Asian Pacific), DTCC China, Oracle Code.. . Joel has always been known for being a pioneer in Oracle technology since the early days of his career being the first Latin American awarded as “OTN Expert” at year 2003 by Oracle Corp., one of the first “Oracle ACE” globally in the Oracle ACE Program at year 2004. He was honoured as one of the first “OCM Database Cloud Administrator” & Maximum Availability OCM in the world. Currently Joel works as Senior Cloud Database Architect in “Yunhe Enmo (Beijing) Technology Co.,Ltd”., company located in Beijing, ChinaEn.enmotech.com
Skant Guptais an Oracle Certified Cloud Professional in Oracle Database 12c, an Oracle Certified Expert in Oracle Real Application Clusters (Oracle RAC) in Oracle Database 11g and 12c, and an Oracle Exadata Certified and an Oracle Certified Professional in Oracle Database 10g, 11g, and 12c. He works at Vodafone Technology in the UK and formerly worked as a senior DBA at Etisalat in Dubai. He has six years of experience with various Oracle technologies, focusing mainly on Cloud, database, and high availability solutions, Oracle WebLogic Suite, Oracle Exadata and Oracle GoldenGate. He has presented at several Oracle user groups worldwide, most recently in the US, the United Arab Emirates, and the India. Skant website link:oracle-help.co