Oracle GoldenGate 12c for Multitenant Databases

Introduction to Oracle GoldenGate 12c for Oracle Multitenant Container Database

This PDF tutorial is a detailed guide designed to teach database administrators, developers, and IT professionals how to effectively use Oracle GoldenGate 12c for replicating data between Oracle multitenant container databases. Oracle GoldenGate is a high-performance software package for real-time data replication, ensuring transactional consistency between source and target databases. The tutorial walks through setting up GoldenGate with Oracle 12c Multitenant architecture, which allows multiple pluggable databases within a single container database.

Readers will learn how to prepare both source and target databases for replication, configure Extract and Replicat processes to capture and apply data changes, and leverage GoldenGate’s initial load features for seamless synchronization. It also covers practical considerations for managing and monitoring replication tasks, emphasizing best practices for multitenant environments where complexity arises due to container and pluggable database configurations. By the end of this tutorial, users will have the knowledge to implement near real-time data synchronization to support high availability, disaster recovery, and data integration scenarios.

Topics Covered in Detail

• Preparation of Oracle source and target databases for replication
• Creating Oracle GoldenGate Extract and Replicat user accounts with necessary privileges
• Enabling supplemental logging required for data capture
• Configuring Extract parameter files to collect data changes from source tables
• Setting up Replicat parameter files to apply data changes to target databases
• Running initial load extraction and replication to synchronize target data
• Managing GoldenGate processes using GGSCI commands (start, stop, view status)
• Handling change data during ongoing replication to ensure transactional integrity
• Tips on troubleshooting replication failures and using discard files
• Insights into Oracle Multitenant Container Database-specific considerations

Key Concepts Explained

1. Oracle GoldenGate Architecture Oracle GoldenGate works by capturing transactional changes on the source database via the Extract process, storing those changes in trail files, and then applying them to the target database using the Replicat process. This architecture supports real-time data integration and replication without impacting system performance significantly because it reads low-level redo logs or directly queries tables depending on configuration.

2. Multitenant Container Database (CDB) and Pluggable Databases (PDBs) Oracle 12c introduced a multitenant architecture where a container database (CDB) can host multiple pluggable databases (PDBs). This design complicates replication since GoldenGate must be configured to handle common users at the CDB level with appropriate privileges, as well as individual pluggable database schemas.

3. Initial Load and Change Data Capture Synchronization GoldenGate supports an initial load mechanism that extracts the current state of source tables and loads them into the target tables as a batch operation. During this time, changes continue to occur on the source, so GoldenGate captures those changes and applies them after the initial load using the AFTERCSN parameter to prevent data inconsistencies.

4. Checkpointing and Process Management GoldenGate processes maintain checkpoints to record their position in the replication trail files. This ensures that after any restart, Extract and Replicat resume seamlessly without missing or duplicating transactions. Control is maintained via GoldenGate Software Command Interface (GGSCI), allowing administrators to start, stop, and monitor processes.

5. DDL Replication and Error Handling GoldenGate can replicate Data Definition Language (DDL) changes when properly configured (e.g., DDL INCLUDE MAPPED). Additionally, discarded or failed records during replication are logged to discard files for troubleshooting. This ensures data consistency and helps manage schema evolution in replicated environments.

Practical Applications and Use Cases

Oracle GoldenGate 12c replication for Multitenant Container Databases is widely used in enterprise environments that require continuous data availability and integration across systems. Practical applications include:

• High Availability and Disaster Recovery: By replicating transactions near real-time from a production database to a standby, organizations can minimize downtime and quickly failover in the event of failure.
• Data Warehousing and Reporting: GoldenGate can replicate transactional data from OLTP systems to data warehouses in near real-time, allowing fresh data to be available for reporting and analytics without burdening source systems.
• Cloud Migrations and Hybrid Deployments: With multitenant databases running both on-premises and in the cloud, GoldenGate provides a seamless way to synchronize data changes during migration phases or hybrid cloud integration.
• Zero Downtime Upgrades and Maintenance: Using GoldenGate’s synchronization capabilities, upgrades can be performed on target systems in parallel without impacting production, allowing a smooth cutover.
• Multi-region Data Distribution: Companies with geographically distributed databases use GoldenGate to replicate and synchronize data ensuring compliance with local regulations or improving localized response times.

Glossary of Key Terms

• Extract: The GoldenGate process responsible for capturing transactional change data from the source database.
• Replicat: The GoldenGate process applying replicated transactions to the target database.
• Trail Files: Files used by GoldenGate to store captured data changes before they are applied to the target.
• Supplemental Logging: Additional logging enabled on the source database to capture sufficient information for replication integrity.
• Checkpoint: A record of the last processed transaction position to ensure fault-tolerant replication.
• Container Database (CDB): A single Oracle database that includes zero or more pluggable databases.
• Pluggable Database (PDB): A portable collection of schemas and objects that appears as a separate database within a container database.
• DDL (Data Definition Language): SQL commands that define or modify database structures such as tables or indexes.
• GGSCI (GoldenGate Software Command Interface): Command-line interface used to manage and monitor GoldenGate processes.
• Discard File: A file where GoldenGate logs data records that failed replication for analysis and troubleshooting.

Who is this PDF for?

This tutorial is ideal for Oracle database administrators, data integration specialists, and IT professionals involved in database replication, high availability, and data migration projects using Oracle GoldenGate 12c. It benefits those working with Oracle Multitenant architectures who need to understand how to configure GoldenGate for efficient data synchronization in complex environments. Developers seeking to implement or maintain continuous data movement pipelines, as well as architects designing disaster recovery or cloud integration solutions, will find this guide invaluable. Additionally, consultants and technical trainers can leverage this resource to build foundational knowledge or assist clients with Oracle data replication deployments.

How to Use this PDF Effectively

To maximize learning from this tutorial, readers should approach it hands-on by setting up a test Oracle 12c multitenant environment parallel to their study. Follow each step carefully, creating users, setting parameters, and running commands in GoldenGate’s GGSCI interface. Use the example scripts and modify them for your environment to reinforce understanding. Regularly check replication status and reports to observe how changes propagate. It is recommended to customize and adapt parameter files, then experiment with initial loads and ongoing replication. Finally, combine the tutorial with Oracle’s official documentation to deepen knowledge about advanced features and parameters.

FAQ – Frequently Asked Questions

What is Oracle GoldenGate and how does it work in Oracle 12c Multitenant environments? Oracle GoldenGate is a real-time data replication and integration tool that captures and applies transactional changes across Oracle databases. In Oracle 12c Multitenant Container Database (CDB) architecture, GoldenGate uses common users in the root container to ensure replication across pluggable databases (PDBs), enabling seamless data synchronization with transaction integrity.

How do I perform an initial load of data when setting up replication with GoldenGate? The initial load extracts data directly from the source Oracle tables using a batch Extract process, sending it to a batch Replicat process on the target. It is essential to capture the current system change number (SCN) during the initial load to start the Replicat from this point, ensuring no data loss or duplication occurs during replication catch-up.

How can I monitor and troubleshoot Oracle GoldenGate replication processes? You can monitor Extract and Replicat processes using GGSCI commands like INFO or STATUS to check replication health and progress. Viewing REPORT and DISCARD files provides detailed diagnostics and error messages critical for troubleshooting replication issues. Regular use of these outputs helps in maintaining replication integrity and quickly resolving problems.

What steps are needed to safely stop and restart GoldenGate Extract and Replicat? Use GGSCI commands to STOP Extract and Replicat gracefully, allowing processes to finalize and write statistics to report files. Restarting is done similarly using the START command. GoldenGate maintains checkpoints, so processes resume at the correct point to avoid transaction loss or duplication upon restart.

What are the key setup steps for GoldenGate replication in an Oracle 12c Multitenant environment? Key setup includes creating common GoldenGate users with appropriate privileges in the root container, enabling supplemental logging on source tables, configuring Extract and Replicat parameter files, setting initial checkpoints, and starting Manager, Extract, and Replicat processes on respective systems. This setup ensures efficient and reliable multitenant database replication.

Exercises and Projects

The tutorial does not contain explicit exercises or projects but outlines a practical walk-through for setting up Oracle GoldenGate replication in a Multitenant Container Database environment. To reinforce understanding, consider the following project:

Project: Implement Oracle GoldenGate Replication Between Two Oracle 12c Multitenant Databases

Steps:

1. Prepare Source and Target Databases:

• Create sample tables on both source and target PDBs using provided SQL scripts.
• Enable supplemental logging on source tables for the columns involved.

2. Configure GoldenGate Users:

• On source and target, create a common GoldenGate user in the root container with DB admin privileges.

3. Set up Manager Processes:

• Start Manager on source and target systems to coordinate replication operations.

4. Initial Load Setup:

• Capture current SCN from the source database.
• Configure and start Extract for initial data batch extraction.
• Configure and start Replicat to apply initial data load.

5. Enable Real-Time Replication:

• Start real-time Extract to capture ongoing changes on source tables.
• Start real-time Replicat with AFTERCSN option to only apply changes post initial load SCN.

6. Test and Monitor:

• Insert, update, and delete sample records on the source database.
• Use GGSCI commands to monitor Extract and Replicat status and check report files for errors.

Tips for Success:

• Always capture and use the correct SCN during initial load to ensure data consistency.
• Monitor report and discard files frequently to catch and resolve issues early.
• Use the GGSCI INFO and VIEW REPORT commands regularly to track replication health.
• Ensure all GoldenGate parameter files (Extract, Replicat) are correctly structured with proper ordering of commands.

This project consolidates key concepts and operations covered in the tutorial, offering hands-on experience with Oracle GoldenGate replication in the multitenant architecture.