# Columnar Database

Real-time analytics OLAP database

ClickHouse is an open-source column-oriented database built for real-time analytical queries on massive datasets. Its columnar storage with advanced compression and vectorized query execution using SIMD instructions deliver exceptional performance for aggregations and scans. It handles billions of rows per second, supports SQL with analytical extensions, and scales horizontally for petabyte-scale data warehousing and real-time dashboards.

In-process analytical SQL database

DuckDB is a high-performance analytical database that runs as an in-process SQL OLAP engine. Unlike traditional client-server databases, DuckDB embeds directly within your application, similar to SQLite but optimized for analytical queries. It supports complex SQL including window functions, CTEs, and nested types while processing columnar data with vectorized execution. DuckDB reads Parquet, CSV, JSON, and Arrow formats natively and integrates with Python and R data science workflows.