Using Materialized Views and Oracle GoldenGate in Oracle 23c

In Oracle 23c, the recommended approach for replicating and synchronizing data across distributed environments has moved away from legacy technologies like primary key snapshots and Advanced Replication. Instead, Oracle supports two modern solutions:

• Materialized Views (MVs) for query optimization and partial data replication.
• Oracle GoldenGate for real-time, high-performance replication and change data capture.

Materialized Views (MVs) are schema objects that store the results of a query physically and allow efficient refresh mechanisms to keep data in sync. They are typically used in data warehousing, reporting, and caching scenarios.
Key Features in 23c:

• Fast refresh using Materialized View Logs.
• Support for Automatic Refresh Schedules (ON COMMIT or ON DEMAND).
• Enhanced support for incremental refreshes.
• New optimizer enhancements to rewrite queries using MVs automatically.

Example: Creating a Materialized View with Fast Refresh

-- Step 1: Create a materialized view log on the base table
CREATE MATERIALIZED VIEW LOG ON employees
WITH PRIMARY KEY, ROWID, SEQUENCE
INCLUDING NEW VALUES;

-- Step 2: Create the materialized view
CREATE MATERIALIZED VIEW mv_employees
BUILD IMMEDIATE
REFRESH FAST ON COMMIT
AS
SELECT employee_id, first_name, last_name, department_id
FROM employees;

For real-time, fault-tolerant replication across heterogeneous systems, Oracle GoldenGate is the preferred solution in Oracle 23c. Unlike legacy replication methods, GoldenGate supports:

1. Real-time change data capture (CDC): Real-time Change Data Capture (CDC):
   Oracle GoldenGate’s real-time change data capture (CDC) capability allows organizations to continuously track and replicate data changes as they occur, ensuring minimal latency between source and target systems. By extracting transactional changes directly from database logs, GoldenGate captures inserts, updates, and deletes with precision, enabling businesses to maintain up-to-date data across heterogeneous environments. This feature is particularly valuable for applications requiring real-time analytics, reporting, or synchronization, as it eliminates the delays inherent in batch processing and provides a seamless flow of data without impacting the performance of the source system.
2. Unidirectional, bidirectional, and multi-master replication:
   Unidirectional, Bidirectional, and Multi-Master Replication: GoldenGate’s flexibility in replication topologies—unidirectional, bidirectional, and multi-master—sets it apart as a strategic tool for diverse use cases. Unidirectional replication efficiently moves data from a single source to one or more targets, ideal for reporting or disaster recovery. Bidirectional replication enables two-way data synchronization, allowing active-active configurations where both systems can process transactions simultaneously. Multi-master replication takes this further, supporting complex environments where multiple systems act as active sources, ensuring data consistency and availability across distributed architectures, all while handling conflict resolution with customizable rules.
3. Replication between on-premise and cloud databases: Replication Between On-Premise and Cloud Databases:
   Oracle GoldenGate bridges the gap between on-premise and cloud environments, offering seamless replication across hybrid infrastructures. This capability is critical as organizations increasingly adopt cloud strategies while maintaining legacy systems on-site. GoldenGate supports integration with major cloud platforms, such as Oracle Cloud, AWS, Azure, and Google Cloud, allowing data to flow securely and efficiently between disparate systems. Whether migrating data to the cloud, maintaining hybrid operational databases, or enabling real-time data warehousing, GoldenGate ensures compatibility and performance across these varied ecosystems.
4. Zero-downtime upgrades and migrations: Zero-Downtime Upgrades and Migrations:
   GoldenGate’s zero-downtime upgrade and migration feature empowers organizations to modernize their database infrastructure without interrupting business operations. By replicating data in real time from an old system to a new one, GoldenGate allows the target environment to be fully synchronized before the switchover, minimizing risk and ensuring continuity. This is especially beneficial for upgrading to Oracle 23c or migrating to new hardware, operating systems, or cloud platforms, as it eliminates the need for scheduled outages, preserves data integrity, and provides a fallback option if issues arise during the transition.

• Use Cases:
  • High availability and disaster recovery (HA/DR).
  • Real-time reporting across different systems.
  • Multi-region deployments.
  • Active-active configurations.
• Benefits:
  • Minimal impact on source systems.
  • Supports heterogeneous environments (e.g., Oracle to MySQL, SQL Server).
  • Strong integration with Oracle Autonomous Database and OCI services.

Feature	Materialized Views	Oracle GoldenGate
Refresh Interval	Scheduled or on-commit	Near real-time
Replication Type	Query result set	Row-level DML changes
Use Case	Reporting, caching, summaries	High-performance, real-time replication
Data Volume	Small to moderate	Medium to very large
Platform Flexibility	Oracle-only	Oracle and non-Oracle systems
Complexity & Licensing	Simple (included with DB license)	Advanced (separate licensing)

Conclusion: Oracle 23c emphasizes modern, scalable, and efficient data replication. While primary key snapshots and Advanced Replication served their purpose in earlier versions, Oracle now encourages the use of:

• Materialized Views for partial replication and performance optimization.
• Oracle GoldenGate for robust, enterprise-class replication and real-time data movement.

Migrating away from deprecated replication methods ensures continued support, better performance, and access to advanced features in the Oracle database ecosystem.