Introduction
Oracle Database is very well known for its high availability and disaster recovery capabilities using Oracle RAC and Oracle (Active) Data Guard. Maintenance operations like patching and upgrade, failures like database server or database instance crashes, and even complete data center outages have no to minimal impact on database availability.
However, what happens on the application side during these errors and interruptions? Especially when those happen at the least favorable time while end users are in the middle of their transactions?
Nothing! If you use Oracle Application Continuity!
Why should everyone care about Application Continuity
Developers
- Application Continuity makes failure and maintenance events completely transparent to your application by reconnecting interrupted sessions and replaying in-flight work on another Oracle RAC instance or on Active Data Guard standby (Actually even more! Stay tuned for the next blog posts).
- Transactions replayed by Application Continuity will not be applied more than once.
- Applications and end users do not encounter any error messages. At most a slight delay in transaction execution.
- No application code changes are required! Only configuration changes.
- Simplified management by eliminating the need to restart and recover applications after database disruption events.
- It’s not mandatory to use Connection Pools (even though still recommended). This makes it even easier for existing applications to use Application Continuity.
- It works everywhere: on-premises, Cloud@Customer, Hybrid Cloud, Oracle Cloud, Non-Oracle Clouds, Oracle Autonomous Database including Always Free instances.
DBAs
- Higher flexibility for performing maintenance tasks as these do not impact application availability.
- Fewer service requests from application owners to maintain and solve after database failures.
- Patching doesn’t necessarily need to be at weekends and nights.
Sales
- Application Continuity is free! Well, let’s rather say it comes at no additional cost. Application Continuity is included in the Oracle RAC or Active Data Guard option license.
- Application Continuity is included in the Oracle Autonomous Database service, even if you are using Bring Your Own License (BYOL) model without Oracle RAC or Active Data Guard option license.
- Make benefits of features that are already included in your option license for a higher Return On Investment (ROI).
Decision Makers
- Enhanced availability and resiliency while you continue serving your customers during maintenance and outage events.
- Increased data consistency improves customer satisfaction and compliance with regulatory requirements.
- In summary, enhanced business continuity: Downtime = no service = lost in revenue
End Users
For me as a user, one of the most frustrating things is when I spend ten minutes filling out a form, e.g. booking a flight, click on submit, and then:
An unexpected error occurred. Please try again later.
What if the booking was already successful in the backend? Should I book again?
Application Continuity automatically replays interrupted transactions, ensures data consistency, and provides a much better user experience.
Summary
Application Continuity makes database maintenance and outages fully transparent to applications and end users. It does not require any application code changes and is included in the Oracle RAC and Active Data Guard option license and in Oracle Autonomous Database.
Application Continuity makes the life of developers and DBAs much easier, improves the end-user experience and satisfaction tremendously, and increases availability and business continuity at no additional cost.
Database Heartbeat 