Pg_lake 3.5: Universal Iceberg REST Catalog Support for Postgres

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ENGINEERING BLOG

Inside the Data Cloud

ENGINEERING BLOG

Inside the Data Cloud

Core Platform

Gen AI

Machine Learning

Blog/Core Platform/pg_lake 3.5: Universal Iceberg REST Catalog Support for Postgres

Oct 12, 2026/8 min readCore Platform

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pg_lake 3.5: Universal Iceberg REST Catalog Support for Postgres

Richie Bachala

pg_lake 3.5 lets Postgres query Apache Iceberg™ tables through REST catalogs beyond Apache Polaris including Lakekeeper and Nessie, and use storage credentials vended by the catalog. Writable tables are currently supported on Apache Polaris only. The next pg_lake release adds automatic prefix discovery, clearer errors for a misconfigured catalog, unauthenticated catalogs for dev/test, and Unity Catalog support.

Apache Iceberg makes table data portable: Write from one engine, read from any other. The Iceberg REST Catalog specification extends that portability to metadata: a single HTTP contract for discovering namespaces, loading table metadata, and committing new snapshots.

pg_lake, Snowflake's open source Postgres extension, brings Postgres into the Iceberg ecosystem. It lets Postgres read and write Iceberg tables in object storage, participating in a lakehouse rather than sitting beside it. pg_lake has included an Iceberg REST catalog client from the start, and its URLs assume the Apache Polaris layout.

We’re excited to announce that the pg_lake 3.5, released in September 2026, and its REST catalog client are no longer tied to the Polaris URL layout.

Once Postgres can talk to the same REST catalog as the rest of your lakehouse, it stops being a separate island. A few things follow from that:

If Postgres speaks to the central Iceberg catalog, an application can write a transaction directly to the lakehouse format. Analytical engines can instantly query that exact same data without it ever being duplicated or moved. Writing through the catalog is supported on Apache Polaris today; other catalogs are read-only for now (tracked in #690).

Postgres can now directly query the central Iceberg catalog using standard SQL. The application can instantly display advanced analytics to the user right alongside their live transactional data, without data teams having to build pipelines to sync the data back.

Developers aren't locked into a specific vendor's ecosystem. A standard Postgres application can natively query tables created and analyzed by other systems, all securely mediated by the shared catalog API.

Instead of managing security rules in Postgres and in the data warehouse, governance can be handled at the catalog layer. When pg_lake requests access to an Iceberg table, the catalog decides whether Postgres can see it and which storage credentials it gets, the same way it does for every other engine.