Oracle GoldenGate Initial Load Methods : Direct Load and Direct Bulk Load

Oracle GoldenGate Initial Load Methods

Initial Load Direct Load

Overview:
Initial Load Direct Load is a method that streams the initial data from the source to the target in real-time. This approach utilizes the Extract and Replicat processes to capture and apply data changes continuously.

• Continuous Capture and Apply: The Extract process reads the data from the source and sends it directly to the target Replicat process, which applies the data immediately.
• Real-Time Data Streaming: It ensures that the data is streamed in real-time, which is beneficial for scenarios where minimizing latency is crucial.
• No Intermediate Files: Unlike some other methods, there are no intermediate files or staging areas; the data moves directly from source to target.
• Transaction Consistency: Ensures transactional consistency, making it suitable for environments where maintaining the exact transactional state is essential.
• Suitable for environments where the data volume is moderate to high, and maintaining low latency is important.
• Ideal for scenarios where transactional consistency is crucial.

Direct Bulk Load

Overview:
Direct Bulk Load is a method designed to handle large volumes of data efficiently by leveraging the bulk loading capabilities of the database management system. This approach is generally faster for loading large datasets compared to the Initial Load Direct Load method.

• Batch Processing: Data is extracted in batches and then loaded into the target system in bulk.
• Use of Database Bulk Load Utilities: Utilizes the native bulk loading utilities provided by the database management system (e.g., SQL*Loader for Oracle databases).
• High Throughput: Optimized for high throughput, making it suitable for loading very large datasets quickly.
• Intermediate Staging: May involve intermediate files or staging areas to store the data temporarily before loading.
• Best suited for initial loads where a very large volume of data needs to be loaded into the target system in a relatively short period.
• Ideal for one-time or infrequent data loads where the primary concern is speed and efficiency rather than real-time streaming or transactional consistency.

Comparison

Feature	Initial Load Direct Load	Direct Bulk Load
Data Movement	Real-time streaming	Batch processing
Latency	Low latency	Higher latency (bulk batches)
Transactional Consistency	Ensured	May not be ensured (depends on implementation)
Intermediate Staging	No	Yes
Efficiency	Moderate	High for large volumes
Use Cases	Continuous, real-time loads	Large initial loads, high throughput