Polars on Project Wintermute

Polars Adds Join Reordering And SQL Coverage

Mon, 31 Aug 2026 14:00:00 +0000

Polars landed 145 commits on main between 25 August and 31 August 2026. The lazy planner now reorders inner joins using scan cardinality, SQL coverage grew for GROUP BY and DATE literals, and leftover 2.0 APIs now fail with a pointer instead of a generic AttributeError. If you collect large star queries or call pl.sql(..., eager=True), check the plan before you ship.

Polars py-1.44.1 - when/then/otherwise Correctness

Wed, 26 Aug 2026 07:09:34 +0000

Python Polars py-1.44.1 shipped on 26 August 2026, two days after py-1.44.0. The GitHub body names five contributors and lists no diffs. The tag is a correctness patch for when/then/otherwise, which is why the previous Python wheel was yanked.

Polars py-1.44.0 - Iceberg Scan And Cloud IO

Mon, 24 Aug 2026 09:38:40 +0000

Python Polars tagged py-1.44.0 on 24 August 2026. Native scan_iceberg now handles Iceberg schema evolution, V3 deletion vectors, snapshot properties, and object storage paths. The tag is a stable Python release.

Polars py-1.43.2 - Parquet and Arrow Correctness

Sat, 01 Aug 2026 06:28:55 +0000

Python Polars py-1.43.2, published on August 1, 2026, focuses on correctness at Parquet, Iceberg, and Arrow boundaries. The most important change fixes a double counted offset when exporting a sliced Series(Array), with further fixes for enum metadata and Parquet field IDs.

Python Polars 1.43.1 - Query Correctness Fixes

Mon, 27 Jul 2026 12:08:22 +0000

Python Polars 1.43.1 was published on July 27, 2026. This stable patch release concentrates on query correctness, led by fixes for a panic in self joins over Delta or Iceberg scans and undefined behavior in first/last_non_null on an empty chunk. For production data pipelines, those failure fixes matter more than the small expression optimization also included in the release.

Python Polars 1.43.0 - Hive and Streaming Pipeline Changes

Tue, 21 Jul 2026 04:30:53 +0000

Python Polars py-1.43.0, published on July 21, 2026, makes Hive partition awareness the main operator change, with group operations and joins able to organize work around partition keys. The release also tightens streaming sinks, object storage access, and several data interchange paths. GitHub marks it as a regular release, not a prerelease.

Polars py-1.42.1 - Parquet Metadata And Panic Fixes

Tue, 30 Jun 2026 04:58:11 +0000

Python Polars py-1.42.1 was published on June 30, 2026, as a patch release for Polars data pipelines. The most important operator visible change is a set of panic and correctness fixes around Parquet scans, grouped aggregations, projection pushdown, datetime extraction, and replace expressions. This release is not marked as a prerelease.

Polars py-1.42.0 - Cloud IO and Streaming Fixes

Wed, 24 Jun 2026 05:20:43 +0000

Polars py-1.42.0 was published on June 24, 2026 for Python users of the pola-rs/polars project. The most useful change for data engineering teams is the set of cloud IO and parquet read improvements, especially bytes based concurrency control, object store DNS handling, and metadata work for multi file parquet scans.