Clickhouse

https://clickhouse.com/ GitHub: https://github.com/ClickHouse/ClickHouse

Clickhouse is a OLAP, not like Postgres who is a OLTP

• Column based
• Amazing at aggregates

Pros

• Great for managing large amounts of data that doesn’t change very often
  • Analytics
  • Finance
  • Ad bidding
  • Content delivery
  • Log Management
• Fast for aggregates
  • Base it’s column-based
    • In a row-based DB, averaging over a column requires accessing the column value for every row
• Scales better then Postgres
  • CPU increase doesn’t benefit Postgres too much, but does for Clickhouse
  • Clickhouse optimize data in parallel, while Postgres is single process (per connection)
• Distributed
  • Multi-master
  • Cross-region

Cons

• Terrible at mutations
  • because it’s column-based, inserting a row requires modifying all columns
  • Often used along with other row-based DB like Postgres

Reference

• YouTube | Clickhouse | What is Clickhouse?
• YouTube | PostHog | In-depth: ClickHouse vs PostgreSQL
  • PostHog migrated to ClickHouse to solve performance issues