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 QuestDB so you can quickly see how they compare against each other.

The primary purpose of this article is to compare how ClickHouse and QuestDB 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 QuestDB Breakdown


 
Database Model

Columnar database

Time series database

Architecture

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

QuestDB is designed for horizontal scaling, enabling you to distribute data and queries across multiple nodes for increased performance and availability. It can be deployed on-premises, in the cloud, or as a hybrid solution, depending on your infrastructure needs and preferences.

License

Apache 2.0

Apache 2.0

Use Cases

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

Monitoring, observability, IoT, Real-time analytics, Financial services, High-frequency trading

Scalability

Horizontally scalable, supports distributed query processing and parallel execution

High-performance with support for horizontal scaling and multi-threading

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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.

QuestDB Overview

QuestDB is an open-source relational column-oriented database designed specifically for time series and event data. It combines high-performance ingestion capabilities with SQL analytics, making it a powerful tool for managing and analyzing large volumes of time-based data. QuestDB addresses the challenges of handling high throughput and provides a simple way to analyze ingested data through SQL queries. It is well-suited for use cases such as financial market data and application metrics.


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.

QuestDB for Time Series Data

QuestDB excels in managing and analyzing time series data. With its high-performance ingestion capabilities, it can handle high data throughput, making it suitable for real-time data ingestion scenarios. QuestDB’s SQL extensions for time series enable users to perform real-time analytics and gain valuable insights from their time-stamped data. Whether it’s financial market data or application metrics, QuestDB simplifies the process of ingesting and analyzing time series data through its fast SQL queries and operational simplicity.


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.

QuestDB Key Concepts

  • Time Series: QuestDB focuses on time series data, which represents data points indexed by time. It is optimized for storing and processing time-stamped data efficiently.
  • Column-Oriented: QuestDB employs a column-oriented storage format, where data is organized and stored column by column rather than row by row. This format enables efficient compression and faster query performance.
  • SQL Extensions: QuestDB extends the SQL language with functionalities specifically tailored for time series data. These extensions facilitate real-time analytics and allow users to leverage familiar SQL constructs for querying time-based data.


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.

QuestDB Architecture

QuestDB follows a hybrid architecture that combines features of columnar and row-based databases. It leverages a column-oriented storage format for efficient compression and query performance while retaining the ability to handle relational data with SQL capabilities. QuestDB supports both SQL and NoSQL-like functionalities, providing users with flexibility in their data modeling and querying approaches. The database consists of multiple components, including the ingestion engine, storage engine, and query engine, working together to ensure high-performance data ingestion and retrieval.

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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.

QuestDB Features

High-Performance Ingestion

QuestDB is optimized for high throughput ingestion, allowing users to efficiently ingest large volumes of time series data at high speeds.

Fast SQL Queries

QuestDB provides fast SQL queries for analyzing time series data. It extends the SQL language with time series-specific functionalities to assist with real-time analytics.

Operational Simplicity

QuestDB aims to provide a user-friendly experience with operational simplicity. It supports schema-agnostic ingestion using popular protocols such as InfluxDB line protocol and PostgreSQL wire protocol. Additionally, a REST API is available for bulk imports and exports, simplifying data management tasks.


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.

QuestDB Use Cases

Financial Market Data

QuestDB is well-suited for managing and analyzing financial market data. Its high-performance ingestion and fast SQL queries enable efficient processing and analysis of large volumes of market data in real time.

Application Metrics

QuestDB can be used for collecting and analyzing application metrics. Its ability to handle high data throughput and provide real-time analytics capabilities makes it suitable for monitoring and analyzing performance metrics, logs, and other application-related data.

IoT Data Analysis

QuestDB’s high-performance ingestion and time series analytics capabilities make it a valuable tool for analyzing IoT sensor 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.

QuestDB Pricing Model

QuestDB is an open-source project released under the Apache 2 License. It is freely available for usage and does not require any licensing fees. Users can access the source code on GitHub and deploy QuestDB on their own infrastructure without incurring direct costs. QuestDB also offers a managed cloud service.