Runbook for Migration from Hadoop to ChistaDATA’s ClickHouse


The landscape of data analytics is evolving rapidly, and businesses are increasingly demanding real-time insights for faster decision-making. Hadoop, a popular big data processing framework, has been widely used for its ability to handle large volumes of data. However, its batch processing nature and complexity make it less suitable for real-time analytics. In this technical blog, we will explore the migration from Hadoop to ClickHouse, a high-performance columnar database, specifically focusing on real-time analytics use cases. We will cover the key considerations, challenges, and steps involved in the migration process.

Understanding the Limitations of Hadoop for Real-Time Analytics:

Hadoop, with its MapReduce processing model, is primarily designed for batch processing and is not optimized for real-time analytics. Some of the limitations of Hadoop for real-time analytics include:

  1. High Latency: Hadoop’s batch processing nature introduces latency in data processing, resulting in delayed insights.
  2. Scalability Challenges: Scaling Hadoop clusters to handle real-time data processing can be complex and resource-intensive.
  3. Data Ingestion Complexity: Hadoop requires additional frameworks and processes for real-time data ingestion, making it less efficient for streaming data.
  4. Query Performance: Hadoop’s disk-based processing and lack of indexing can lead to slower query performance, especially for complex analytical queries.
  5. Operational Complexity: Hadoop’s distributed nature requires specialized skills for cluster management, maintenance, and monitoring.

Migration Steps from Hadoop to ClickHouse for Real-Time Analytics:

  1. Assess Use Case Requirements:
  • Understand the specific requirements and use cases driving the need for real-time analytics.
  • Identify the data sources, volume, velocity, and analytics requirements.
  1. Data Modeling and Schema Design:
  • Analyze the existing data model in Hadoop and design an appropriate schema for ClickHouse.
  • Leverage ClickHouse’s columnar storage format and indexing capabilities for efficient data retrieval.
  1. Data Extraction and Transformation:
  • Extract the relevant data from Hadoop and transform it into a format compatible with ClickHouse.
  • Use ETL (Extract, Transform, Load) processes or data integration tools to ensure data consistency and quality.
  1. Data Ingestion into ClickHouse:
  • Develop a robust data ingestion pipeline from the source systems to ClickHouse.
  • Utilize ClickHouse’s native data ingestion mechanisms, such as Kafka integration or direct INSERT operations, for efficient and real-time data loading.
  1. Query Migration and Optimization:
  • Analyze the existing queries in Hadoop and rewrite them in ClickHouse-compatible SQL.
  • Leverage ClickHouse’s advanced analytics functions and query optimization techniques for enhanced performance.
  1. Data Validation and Quality Assurance:
  • Perform thorough data validation and quality checks to ensure the accuracy and consistency of the migrated data.
  • Develop automated tests and validation scripts to verify the correctness of the migrated analytics results.
  1. System Integration and Monitoring:
  • Integrate ClickHouse with existing data processing and visualization tools for seamless integration into the analytics ecosystem.
  • Implement monitoring mechanisms to track query performance, resource utilization, and system health.
  1. User Training and Adoption:
  • Conduct training sessions and workshops to familiarize users with ClickHouse’s features, SQL syntax, and best practices.
  • Encourage user adoption and provide ongoing support to ensure a smooth transition from Hadoop to ClickHouse.

Benefits of Migrating to ClickHouse for Real-Time Analytics:

  1. Real-Time Insights: ClickHouse’s performance optimizations and columnar storage enable real-time analytics, providing faster insights for timely decision-making.
  2. Scalability and Performance: ClickHouse’s distributed architecture and query optimizations allow for high scalability and improved query performance compared to Hadoop.
  3. Simplified Operations: ClickHouse’s ease of use, simplified management, and monitoring capabilities reduce operational complexity compared to managing Hadoop clusters.
  4. Low Latency: ClickHouse’s efficient data storage and indexing techniques result in low-latency query responses, enabling real-time analytics.
  5. SQL Compatibility: ClickHouse’s SQL compatibility allows for seamless migration of existing Hadoop queries, reducing the learning curve for users.
  6. Advanced Analytics Functions: ClickHouse offers a rich set of built-in analytics functions and libraries, enabling advanced analytics without additional external dependencies.


Migrating from Hadoop to ClickHouse for real-time analytics is a strategic move to address the limitations of batch processing and achieve faster insights. ClickHouse’s performance, scalability, low-latency querying, and SQL compatibility make it an ideal choice for real-time analytics workloads. By following the outlined migration steps and leveraging ClickHouse’s capabilities, businesses can unlock the potential of real-time analytics, gain actionable insights, and make data-driven decisions in a timely manner. Embracing ClickHouse as the foundation for real-time analytics opens up new possibilities for businesses to thrive in the era of fast-paced data-driven decision-making.

To know more about ClickHouse v/s Hadoop for real-time analytics, do consider reading the following articles:

ChistaDATA: Your Trusted ClickHouse Consultative Support and Managed Services Provider. Unlock the Power of Real-Time Analytics with ChistaDATA Cloud( – the World’s Most Advanced ClickHouse DBaaS Infrastructure. Contact us at or (844)395-5717 for tailored solutions and optimal performance.

About Shiv Iyer 227 Articles
Open Source Database Systems Engineer with a deep understanding of Optimizer Internals, Performance Engineering, Scalability and Data SRE. Shiv currently is the Founder, Investor, Board Member and CEO of multiple Database Systems Infrastructure Operations companies in the Transaction Processing Computing and ColumnStores ecosystem. He is also a frequent speaker in open source software conferences globally.