pg_mooncake
maintenanceby Mooncake Labs (Databricks) · since 2024 · also known as Mooncake, moonlink
Postgres extension that mirrors tables into Iceberg columnstores for real-time analytics via DuckDB.
maintenance. Mooncake Labs was acquired by Databricks (Oct 2025) for Lakebase; the public repo has had no commits since Oct 2025.
Overview
pg_mooncake adds real-time analytics to PostgreSQL by maintaining a columnstore mirror of regular Postgres tables in Apache Iceberg, fed by the moonlink engine with sub-second freshness for inserts, updates and deletes. Analytical queries run through DuckDB (it is now a sub-extension of pg_duckdb), while other engines can read the Iceberg tables directly. Databricks acquired Mooncake Labs in October 2025 to strengthen its Postgres-based Lakebase, and the public repo has seen almost no activity since, so treat it as promising technology with an uncertain open-source future.
Strengths & trade-offs
Strengths
- +Analytics on live Postgres tables without ETL
- +Columnstore mirror written as open Iceberg tables
- +DuckDB execution ranks near the top of ClickBench
- +MIT-licensed
Trade-offs
- −Development has stalled since the Databricks acquisition
- −Young code base with few production references
- −Requires pg_duckdb and a Rust build toolchain
Great for
- +Real-time dashboards on Postgres data
- +Mirroring Postgres tables to Iceberg
- +HTAP experiments
Think twice for
- −Production systems needing long-term support
- −Multi-node analytics at scale
Capabilities
Native or official first-party support · 6 of 25 tracked
Scale & consistency
- Comfortable data size
- Small · ≤ 100 GB
- Horizontal scaling
- None
- Multi-region
- No
- Transactions
- Full ACID
- Consistency
- Strong
- Schema
- Strict
- Architecture
- Single node, Client server
- Query languages
- SQL, PL/pgSQL
Runs inside one Postgres instance; columnstore data can live in object storage as Iceberg.
Deployment
Ecosystem
Alternatives to pg_mooncake
PostgreSQL extension that embeds DuckDB's vectorized engine for fast analytics and data-lake queries.
pg-mooncake vs pg-duckdb →Columnar storage extension for Postgres from Hydra; dormant after the team joined Supabase in 2026.
pg-mooncake vs hydra-columnar →Postgres extension that shards tables across nodes for multi-tenant SaaS and real-time analytics.
pg-mooncake vs citus →Databricks' serverless Postgres built on Neon tech, with branching and sync to Delta tables in Unity Catalog.
pg-mooncake vs lakebase →In-process columnar SQL database: the SQLite of analytics, running inside your app or notebook.
pg-mooncake vs duckdb →Open-source columnar OLAP database known for very fast aggregations over billions of rows.
pg-mooncake vs clickhouse →pg_mooncake FAQ
What is pg_mooncake?
pg_mooncake is a columnar / OLAP database by Mooncake Labs (Databricks), first released in 2024. pg_mooncake adds real-time analytics to PostgreSQL by maintaining a columnstore mirror of regular Postgres tables in Apache Iceberg, fed by the moonlink engine with sub-second freshness for inserts, updates and deletes. Analytical queries run through DuckDB (it is now a sub-extension of pg_duckdb), while other engines can read the Iceberg tables directly. Databricks acquired Mooncake Labs in October 2025 to strengthen its Postgres-based Lakebase, and the public repo has seen almost no activity since, so treat it as promising technology with an uncertain open-source future.
Is pg_mooncake open source?
Yes. pg_mooncake is open source. License: MIT License.
Does pg_mooncake support ACID transactions?
Yes. pg_mooncake supports full ACID transactions, with strong consistency.
Does pg_mooncake scale horizontally?
pg_mooncake does not scale horizontally; it runs on a single node, so you scale it up rather than out. It is comfortable at small scale (≤ 100 GB).
How can I run pg_mooncake?
You can self-host it.
What is pg_mooncake best for?
pg_mooncake is a strong fit for real-time dashboards on Postgres data, mirroring Postgres tables to Iceberg and HTAP experiments. Think twice for production systems needing long-term support.
What are the best alternatives to pg_mooncake?
Common alternatives to pg_mooncake include pg_duckdb, Hydra, Citus, Databricks Lakebase and DuckDB. The right choice depends on your workload, scale and hosting; WhichDB's smart match ranks them against your requirements.
Is pg_mooncake still maintained?
pg_mooncake is in maintenance mode. Mooncake Labs was acquired by Databricks (Oct 2025) for Lakebase; the public repo has had no commits since Oct 2025.
How popular is pg_mooncake?
pg_mooncake ranks #285 of 844 databases on the WhichDB Score (11.2/100), and #29 among columnar / OLAP databases. The score combines public adoption signals such as package downloads, GitHub activity, job posts and developer discussion.