Clickhouse Has a Free Column-Oriented Database That Queries Billions of Rows in Seconds

#clickhouse #database #analytics #opensource

ClickHouse is a column-oriented OLAP database. It processes analytical queries on billions of rows in real-time — used by Cloudflare, eBay, and Uber.

What You Get for Free

Column storage — 10-100x compression
Vectorized execution — SIMD optimized
SQL — standard SQL with extensions
Real-time ingestion — millions of rows/sec
Materialized views — pre-aggregated data
Distributed — horizontal scaling
ClickHouse Cloud — free trial

Quick Start

docker run -p 8123:8123 -p 9000:9000 clickhouse/clickhouse-server

Analytical Queries

CREATE TABLE events (
  timestamp DateTime,
  user_id UInt64,
  event String,
  properties String
) ENGINE = MergeTree()
ORDER BY (timestamp, user_id);

-- Query 1 billion rows in <1 second
SELECT event, count(), uniq(user_id)
FROM events
WHERE timestamp > now() - INTERVAL 7 DAY
GROUP BY event
ORDER BY count() DESC;