AI Weekly Malaysia

Polars 2.0 release candidate is out, with the biggest change being that LazyFrame collect() now defaults to the streaming engine instead of the in-memory engine, expecting ~5x performance improvements and lower memory usage. Row order is no longer guaranteed for joins, group_by, and unpivot unless you set maintain_order=True, and stricter schema validation is emphasized with collect_schema() for early error detection.

Why: If you use Polars in pipelines, your query results may now arrive in different row order after upgrading—audit any join/group_by/unpivot where order matters and add maintain_order=True or pin engine='in-memory'. The collect_schema() method is worth adopting if you're building AI agent workflows that generate Polars queries, since it lets agents validate schema without materializing data.