What Is Oracle Change Data Capture – An Overview

 Oracle Change Data Capture (CDC) is a software pattern that detects and captures changes made to an Oracle database. Types of changes include insert, delete, and update actions. This cutting-edge technology is a critical component of the Oracle replication process, where changes made to data in a relational format are identified and recorded to be used in ETL, EAI, and any other applications.

There are several benefits of Oracle Change Data Capture. Most important for businesses is cost effectiveness, since Oracle CDC extracts and loads data into the data warehouse or other data storage incrementally in real-time. Hence, there is no need to refresh the full data in bulk whenever any changes are made at the source.  

Types of Oracle Change Data Capture

There are two types of Oracle CDC.

Synchronous Change Data Capture

In this mode, triggers are inserted into entries in a change table whenever data is modified. These are then activated whenever any changes are identified. The process is started by creating a user that will act as a change data publisher. Next, a changeset and tables have to be created that will subscribe to the changes.

The downside of this type of Oracle Change Data Capture is that the performance of the source database is affected by the placement of the triggers. 

Asynchronous Change Data Capture

In this form of Oracle Change Data Capture, the redo logs are used to keep a record of all changes taking place in the Oracle database. The benefit here is that there is no degradation in the performance of the source database, unlike the previous mode.

Businesses must carefully select the form of Oracle Change Data Capture that matches all their operational requirements.  

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