Choosing the right database is a critical choice when building any software application. All databases have different strengths and weaknesses when it comes to performance, so deciding which database has the most benefits and the most minor downsides for your specific use case and data model is an important decision. Below you will find an overview of the key concepts, architecture, features, use cases, and pricing models of ClickHouse and Kdb so you can quickly see how they compare against each other.

The primary purpose of this article is to compare how ClickHouse and Kdb perform for workloads involving time series data, not for all possible use cases. Time series data typically presents a unique challenge in terms of database performance. This is due to the high volume of data being written and the query patterns to access that data. This article doesn’t intend to make the case for which database is better; it simply provides an overview of each database so you can make an informed decision.

ClickHouse vs Kdb Breakdown


 
Database Model

Columnar database

Time series and columnar database

Architecture

ClickHouse can be deployed on-premises, in the cloud, or as a managed service.

Kdb can be deployed on-premises, in the cloud, or as a hybrid solution.

License

Apache 2.0

Closed source

Use Cases

Real-time analytics, big data processing, event logging, monitoring, IoT, data warehousing

High-frequency trading, financial services, market data analysis, IoT, real-time analytics

Scalability

Horizontally scalable, supports distributed query processing and parallel execution

Highly scalable with multi-threading and multi-node support, suitable for large-scale data processing

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ClickHouse Overview

ClickHouse is an open source columnar database management system designed for high-performance online analytical processing (OLAP) tasks. It was developed by Yandex, a leading Russian technology company. ClickHouse is known for its ability to process large volumes of data in real-time, providing fast query performance and real-time analytics. Its columnar storage architecture enables efficient data compression and faster query execution, making it suitable for large-scale data analytics and business intelligence applications.

Kdb Overview

kdb+ is a high-performance columnar, time series database developed by Kx Systems. Released in 2003, kdb+ is designed to efficiently manage large volumes of data, with a primary focus on financial data, such as stock market trades and quotes. It is built on the principles of the q programming language, which is a descendant of APL and K. The database is known for its speed, scalability, and ability to process both real-time and historical data.


ClickHouse for Time Series Data

ClickHouse can be used for storing and analyzing time series data effectively, although it is not explicitly optimized for working with time series data. While ClickHouse can query time series data very quickly once ingested, it tends to struggle with very high write scenarios where data needs to be ingested in smaller batches so it can be analyzed in real time.

Kdb for Time Series Data

kdb+ is designed to store time series data, making it a natural fit for applications that require high-speed querying and analysis of large volumes of data. Its columnar storage format allows for efficient compression and retrieval of time series data, while its q language provides a powerful and expressive means to manipulate and analyze the data. kdb+ is especially strong for financial data, though it can be used for other types of time series data as well.


ClickHouse Key Concepts

  • Columnar storage: ClickHouse stores data in a columnar format, which means that data for each column is stored separately. This enables efficient compression and faster query execution, as only the required columns are read during query execution.
  • Distributed processing: ClickHouse supports distributed processing, allowing queries to be executed across multiple nodes in a cluster, improving query performance and scalability.
  • Data replication: ClickHouse provides data replication, ensuring data availability and fault tolerance in case of hardware failures or node outages.
  • Materialized Views: ClickHouse supports materialized views, which are precomputed query results stored as tables. Materialized views can significantly improve query performance, as they allow for faster data retrieval by avoiding the need to recompute the results for each query.

Kdb Key Concepts

  • q language: A high-level, domain-specific programming language used for querying and manipulating data in kdb+. It combines SQL-like syntax with a functional programming style.
  • Columnar storage: kdb+ stores data in columns, rather than rows, which allows for faster querying and analysis of time series data.
  • Tables: kdb+ stores data in tables, which are similar to relational tables, but with a focus on columnar storage and time series data.
  • Splayed tables: A table storage format where each column is stored in a separate file, further enhancing query performance.


ClickHouse Architecture

ClickHouse’s architecture is designed to support high-performance analytics on large datasets. ClickHouse stores data in a columnar format. This enables efficient data compression and faster query execution, as only the required columns are read during query execution. ClickHouse also supports distributed processing, which allows for queries to be executed across multiple nodes in a cluster. ClickHouse uses the MergeTree storage engine as its primary table engine. MergeTree is designed for high-performance OLAP tasks and supports data replication, data partitioning, and indexing.

Kdb Architecture

kdb+ is a columnar, time series database that employs a custom data model tailored for efficient storage and querying of time series data. It does not use traditional SQL, but instead relies on the q language for querying and data manipulation. The architecture of kdb+ is designed for both in-memory and on-disk storage, with the ability to scale horizontally across multiple machines. The primary components of kdb+ are the database engine, the q language interpreter, and the built-in web server.

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ClickHouse Features

Real-time analytics

ClickHouse is designed for real-time analytics and can process large volumes of data with low latency, providing fast query performance and real-time insights.

Data compression

ClickHouse’s columnar storage format enables efficient data compression, reducing storage requirements and improving query performance.

Materialized views

ClickHouse supports materialized views, which can significantly improve query performance by precomputing and storing query results as tables.

Kdb Features

High performance

kdb+ is known for its speed and performance, with its columnar storage format and q language allowing for rapid querying and analysis of time series data.

Scalability

kdb+ is designed to scale horizontally, making it suitable for handling large volumes of data across multiple machines.

q language

The q language is a powerful, expressive, and high-level language used for querying and manipulating data in kdb+. It combines SQL-like syntax with a functional programming style.


ClickHouse Use Cases

Large-scale data analytics

ClickHouse’s high-performance query engine and columnar storage format make it suitable for large-scale data analytics and business intelligence applications.

Real-time reporting

ClickHouse’s real-time analytics capabilities enable organizations to generate real-time reports and dashboards, providing up-to-date insights for decision-making.

Log and event data analysis

ClickHouse’s ability to process large volumes of data in real-time makes it a suitable choice for log and event data analysis, such as analyzing web server logs or application events.

Kdb Use Cases

Financial data analysis

kdb+ is widely used in the financial industry for the storage and analysis of stock market trades, quotes, and other time series financial data.

High-frequency trading

kdb+ is a popular choice for high-frequency trading applications due to its high performance and ability to handle large volumes of real-time data.

IoT and sensor data

kdb+ can be used to store and analyze large volumes of time series data generated by IoT devices and sensors, though its primary focus remains on financial data.


ClickHouse Pricing Model

ClickHouse is an open source database and can be deployed on your own hardware. The developers of ClickHouse have also recently created ClickHouse Cloud which is a managed service for deploying ClickHouse.

Kdb Pricing Model

kdb+ is a commercial product, with pricing depending on the deployment model and the number of cores or servers used. Kx Systems offers a free 32-bit version of kdb+ for non-commercial use, with limitations on the amount of memory that can be used. For commercial deployments and full-featured versions, users must contact Kx Systems for pricing details.