A Tour of Polars' Internals: The Twelve Ideas That Explain the Engine
A guided tour of the ideas that make Polars fast: chunked columns, inline strings, arena-allocated expressions, a rewrite-heavy optimizer, morsel pipelines and hash shuffles.
Polars
Polars Spills to Disk Before It Runs Out of Memory
Polars tracks memory with a process-global counting allocator and a budget; nodes register their output frames as spillable, and a global manager writes them to zstd-compressed IPC …
Polars Publishes a Join's Build Side as a Runtime Filter
An optimizer pass traces a join key from the probe side down to a parquet scan, hands the scan a DynamicPred slot, and the join fills that slot with the build side’s key range once …
Polars Runs Queries on Rayon's Global Thread Pool
crates/polars-core/src/runtime.rs wraps every rayon entry point in a zero-sized RAYON marker, which on native builds forwards straight to rayon’s global pool. Polars’ own pools are …
Polars Shares Data With Python Over the Arrow C Data Interface
polars-arrow implements the Arrow C Data Interface: three C structs, a private_data box holding the Rust array, and a release callback that transfers ownership back. Buffers are …