Apache Iceberg, Polaris, and DataFusion push spec and reliability work in busy week

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Between June 24 and July 1, 2026, several Apache open lakehouse projects focused on correctness and standardization rather than new features. Iceberg held two significant votes: one to adopt a shared expressions spec that defines how filters and data transformations behave across implementations, and another to add a specific-name field to the UDF spec so catalogs can reference exact function versions. The expressions vote drew broad community support, with binding and non-binding approvals from multiple contributors who highlighted its potential to unlock new use cases. Polaris worked on multi-database catalog support, welcomed a new committer, and rejected a release candidate for legitimate technical reasons. DataFusion shipped a clean release of its Python bindings, while Arrow rebuilt its benchmarking service and Parquet debated how to handle versioning as features outpace release cycles.

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