Oracle CDC (Change Data Capture) for Real-Time Data Movement and Stream Processing

8 Minute Read

In today’s dynamic business environment, the role of data is increasingly crucial. Historically, significant data was stored in expansive Oracle databases, with its transfer to data warehouses and analysis repositories managed through batch ETL (Extract, Transform, Load) processes. As organizations shift towards cloud-based analytical tools, aiming to harness real-time data insights, they frequently face hurdles in integrating this data smoothly.

Envision a scenario where you can fluidly manage data movement across various systems instantaneously. Oracle Change Data Capture (CDC) represents a groundbreaking method, offering the capability to monitor, analyze, and replicate data modifications in your warehouses swiftly and effectively.

This article aims to explore the complexities of Oracle CDC, discussing its advantages, widespread cloud compatibility and how to get started. In addition, we will highlight the power of leveraging Oracle CDC with Striim, a leading platform in data streaming and integration. This powerful combination equips your organization with the tools necessary to transition into an era of uninterrupted, real-time data analytics, marking a significant stride in business intelligence and decision-making processes.

Table of Contents

What is Oracle CDC?

Oracle CDC, or Change Data Capture, is a feature in Oracle databases that enables the identification and replication of data changes to a target database in real-time. At the most granular level, CDC captures insertions, updates, and deletions applied to database tables and makes this change data available in a format that can be easily consumed by other systems or applications. 

Oracle CDC works by mining database write-ahead logs and internal metadata tables, to capture and store the changes made to the source database. The CDC database configuration is set up to enable the extraction and processing of the captured data changes, which are then applied to the target system. 

These mirror tables propagate the changes from the source database to the target database, ensuring that the data remains consistent between the two databases. Oracle CDC’s functionality allows for real-time data replication, enabling organizations to have up-to-date and accurate data in their target databases for reporting, analysis, and other business processes. Overall, Oracle CDC plays a crucial role in efficiently and effectively identifying and replicating data changes from an Oracle database to a target database.

Understanding Striim and Oracle CDC Integration

  • Real-Time Data Capture: CDC monitors changes to database records (like rows in a table) in real-time. It captures these changes as they occur, without needing to query or load the entire database, thereby reducing the load on the database system.
  • Efficient Data Replication: CDC enables efficient data replication from one database to another or to a data warehouse. This is particularly useful for maintaining up-to-date copies of data across different systems.
  • Supports Data Integration: By capturing changes, CDC facilitates the integration of data into other systems for various purposes like analytics, reporting, or data synchronization.
  • Minimizes Data Loss: CDC ensures that changes are not missed between data refreshes. This minimizes data loss in scenarios where continuous data availability is crucial.
  • Used in Diverse Applications: CDC is widely used in applications like data warehousing, data migration, business intelligence, and real-time analytics.
  • Technology-Dependent: The implementation of CDC depends on the technology and the database systems being used. Different databases might have different mechanisms or tools for CDC.

Change Data Capture is a powerful method for tracking and capturing changes in database data in real time, which is essential for maintaining accurate and current data across diverse systems and applications.

What are the Advantages of Oracle CDC? 

Oracle CDC (Change Data Capture) offers significant advantages for Oracle users. It efficiently identifies and captures new, updated, or deleted data from Oracle Database tables, making it available for broader use. This enables real-time data integration and analysis, allowing businesses to make timely and informed decisions.

Additionally, Oracle CDC offers potential cost savings by reducing the need for manual data extraction and transformation, as well as minimizing the impact on system performance. It also provides licensing flexibility, allowing organizations to scale their data integration capabilities according to their specific needs.

Furthermore, the Oracle CDC Connector provides simplified data pipelines, streamlining the process of moving data from Oracle Databases to other systems or applications. This not only improves operational efficiency but also enables organizations to glean valuable insights from their data in a timely manner.

In conclusion, Oracle CDC is essential for Oracle users as it offers numerous benefits including cost savings, licensing flexibility, and simplified data pipelines, ultimately enhancing their data integration and analysis capabilities.

What are the Alternatives to CDC?

Change Data Capture (CDC) is a method of tracking changes to a database in real-time and capturing those changes to keep a separate copy of the data up-to-date. An alternative to CDC is batch ETL (extract, transform, load) processing.

Batch ETL involves extracting data from source systems, transforming it into the desired format, and then loading it into the target system at scheduled intervals. This method typically results in a delay between the source and target data being synchronized, as it relies on periodic batch processing rather than real-time capture of changes.

One advantage of CDC over batch ETL is its ability to provide near real-time synchronization of data, allowing for more up-to-date reporting and analysis. CDC also reduces the amount of data processed, as it only captures and replicates changes rather than the entire dataset each time.

Oracle CDC Methods

When it comes to change data capture (CDC) methods, log-based CDC is often considered the best method compared to others such as trigger-based CDC. Log-based CDC captures changes directly from the database transaction log, providing a more efficient and real-time method of capturing changes without putting additional load on the database.

Oracle GoldenGate has been a popular tool for log-based CDC, offering robust capabilities for capturing and replicating data changes. However, Striim has emerged as a more advanced option compared to Oracle GoldenGate. The team behind GoldenGate actually founded Striim, leveraging their expertise to create a more sophisticated and feature-rich CDC solution.

Striim offers advanced features such as real-time stream processing, integration with cloud platforms, and support for a wide range of data sources beyond just Oracle databases. Additionally, Striim provides better support for timestamps and handles complex data transformation and processing tasks more efficiently.

In conclusion, log-based CDC methods, such as the one provided by Striim, are better than others due to their efficiency, real-time capabilities, and advanced features. While Oracle GoldenGate has been a popular choice, Striim offers a more advanced and comprehensive solution for change data capture.

Learn more: Oracle Database Replication Methods (and their Pros and Cons) 

How to Configure Your Sources and Targets for Oracle CDC

To configure an Oracle database source for Change Data Capture (CDC) and add a target, first follow the basic oracle configuration task to enable CDC on source oracle database. 

There are three ways you can configure and run a Striim application using flow Designer:

  1. Start from Scratch
  2. Using Striim Wizard
  3. By uploading TQL file

Start from Scratch

If you want to configure your Oracle Source from scratch, click on Create App on the top right and choose Start from scratch. Name your app and click save. You will be redirected to the Flow page where you can choose your source from the list of components on the left. Drag an Oracle CDC source and enter the connection details on the right.

Name: Name of your source adapter

Connection url: jdbc:oracle:thin:@//<instance id>:1521/<SID>

Username: Oracle database username 

Password: database password

Tables: “<database>”.”<tablenames>”

OUTPUT TO: Choose New Output and name your Stream

To add a target to capture CDC data from Oracle source, drag a target from the list of targets under components on the left. Refer to Striim documentation to learn about the configuration steps for your desired target.

Using Striim Wizard

To configure Oracle CDC source to any supported target using Striim wizard, enter Oracle CDC source and your desired target in the ‘Search for templates’ bar next to Create app on top. Name the app and click save. The wizard will prompt you to enter the connection details and validate your connection after each step. You will need the connection details for both your source and target and your pipeline will be ready in few clicks.

Using TQL Files

You can create a .tql  file and Import it on the Flow Designer page to directly run an Oracle CDC pipeline.You can find sample TQL files to try on our recipe github page. Here is a sample TQL code for an Oracle CDC Source.


CREATE OR REPLACE SOURCE oracle_source USING Global.OracleReader ( 
  TransactionBufferDiskLocation: '.striim/LargeBuffer', 
  adapterName: 'OracleReader', 
  DatabaseRole: 'PRIMARY', 
  Compression: false, 
  connectionRetryPolicy: 'timeOut=30, retryInterval=30, maxRetries=3', 
  Password_encrypted: 'true', 
  SupportPDB: false, 
  QuiesceMarkerTable: 'QUIESCEMARKER', 
  FetchSize: 1000, 
  CDDLAction: 'Process', 
  CommittedTransactions: true, 
  QueueSize: 2048, 
  DictionaryMode: 'OnlineCatalog', 
  SetConservativeRange: false, 
  CDDLCapture: false, 
  Password: '***********', 
  Username: 'qatest', 
  TransactionBufferType: 'Memory', 
  ConnectionURL: 'jdbc:oracle:thin:@//***.***.***.***:1521/ORCL', 
  TransactionBufferSpilloverSize: '100MB', 
  FilterTransactionBoundaries: true, 
  SendBeforeImage: true ) 
OUTPUT TO complication_data_stream;


Monitoring Update Operations

To monitor update operations with Striim, start by configuring change data capture (CDC) for the relevant database or data source. This will allow Striim to capture the update change events. The significance of capturing these events lies in the ability to analyze the before and after structures of a row to determine the changes made. This analysis can provide valuable insights into data trends and allow for real-time monitoring of critical updates.

In the payload section of the update change event, key information is provided, including the before and after images of the row, as well as metadata such as the timestamp and operation type. This information can be used to track the timing and nature of update events, enabling users to understand when and how data is being updated.

By leveraging Striim’s capabilities to capture and analyze update change events, organizations can gain a deeper understanding of their data and make informed decisions based on real-time information.

Recovering CDC Pipelines After Downtime or Cluster Failures

Server downtime refers to the period of time when organizations are unable to operate. It can occur either as a result of planned maintenance or IT tasks, or unplanned incidents such as system crashes or connectivity problems.

With few limitations, Striim applications can be recovered after planned downtime or most cluster failures with no loss of data. Striim that can be utilized to handle failovers along with real-time streaming. Striim allows data pipelines to pick up from where it left during the failover, thus avoiding loss of data or duplicates in the target table.

Learn more: Recover your CDC pipeline on Striim after planned downtime or cluster failure with no loss of data

Oracle CDC to BigQuery

Striim’s streaming integration capabilities allow for seamless, no-code integration of Oracle CDC into Google Cloud BigQuery, enabling users to easily replicate and synchronize data from Oracle to BigQuery in real-time. This means that businesses can take advantage of the power of BigQuery for analyzing and visualizing their Oracle data without the need for complex ETL processes or manual data loading.

Learn more: Real-Time Data Streaming from Oracle to Google BigQuery

Oracle CDC to Snowflake

Oracle CDC, augmented with Striim, enables continuous, real-time data loading into BigQuery and Snowflake. Striim’s advanced streaming capabilities complement Oracle CDC’s row filtering and column mapping, offering enhanced data transformation and integration. This leads to more dynamic data analytics and precise insights.

Learn more: Stream data to Snowflake in real-time

Oracle CDC to Azure

Combining Oracle CDC with Striim optimizes data migration and streaming to Azure services. Striim’s platform enhances Azure’s data processing by providing additional features like real-time data analytics, comprehensive monitoring, and simplified management of data flows.

Learn More: Stream data from Salesforce and Oracle to Azure Synapse

Oracle CDC to Databricks

The integration of Striim with Oracle CDC simplifies streaming data directly into Databricks. This synergy not only maintains data consistency but also minimizes latency, allowing businesses to leverage Databricks’ analytics capabilities more effectively.

Learn More: Tutorial: Oracle Change Data Capture to Databricks 

Oracle CDC to to Kafka

By integrating Striim with Confluent Kafka, organizations can achieve a cost-effective, unobtrusive solution for moving transactional data from Oracle databases onto Apache Kafka message queues in real time. This delivery solution is managed through a single application that offers enterprise-level security, scalability, and dependability.

Learn more: Streaming SQL on Kafka with Striim

Oracle CDC to Postgres

Striim enables organizations to generate real value from the transactional data residing in their existing Oracle databases. Using non-intrusive change data capture (CDC), Striim enables continuous data ingestion from Oracle to Postgres with sub-second latency. Users can easily set up ingestion via Striim’s pre-configured CDC wizards, and drag-and-drop UI.

Learn more: Oracle CDC to Postgres 

Why Use Striim for Oracle CDC?

Striim offers a high-speed, error-free change data capture (CDC) solution for Oracle databases, allowing users to capture and deliver real-time data with minimal latency. The Striim OJet Oracle reader can read up to 150+ gigabytes of data per hour from Oracle. With its real-time monitoring and analysis capabilities, Striim empowers organizations to make timely and informed decisions. Additionally, Striim supports over 100 sources/targets, providing flexibility and scalability for diverse data integration needs.

Unlike LogMiner-based or trigger-based Oracle CDC solutions, Striim offers a high-performance alternative with its low-impact, non-intrusive approach to capturing and processing data changes. This design makes it particularly well-suited for mission critical, high-volume environments where performance and reliability are essential. By minimizing the impact on the source database and ensuring data integrity, Striim enables organizations to efficiently and effectively utilize real-time data for decision-making and operational insights. Overall, Striim for Oracle CDC is a powerful solution that addresses the requirements of high-speed, real-time monitoring, and analysis in mission-critical environments.

Watch our recorded webinar, where we provide you with an overview of Striim’s Oracle CDC capabilities 

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