|Apache Arrow 2 Improves C++ and Rust Support|
|Written by Kay Ewbank|
|Thursday, 29 October 2020|
There's a new release of Apache Arrow with improvements to the support for C++ and Rust, particularly in support for Parquet.
The major components of the project include the columnar In-memory format, and an IPC format: that provides a serialization of the Arrow format and associated metadata, for communication between processes and heterogeneous environments. There's also the Arrow Flight RPC protocol that provides a building block for remote services exchanging Arrow data with applications.
Improvements to the C++ support in this release start with Parquet handling. Nested data in Parquet is handled better, and you can read and write arbitrarily nested data, including extension types with a nested storage type. This had the side-effect of fixing several bugs in writing nested data and FixedSizeList. Parquet datasets can also now be written with partitions, including control over accumulation of statistics for individual columns. Other C++ improvements include the addition of compute kernels for standard deviation, variance, and mode, and improvements to S3 support, including automatic region detection.
C# support has also been improved, with the addition of full support for Struct types, and the addition of synchronous write APIs for ArrowStreamWriter and ArrowFileWriter.
R Support has been enhanced with the ability to write multi-file datasets with partitioning to Parquet or Feather. You can also now read and write directly to AWS S3.
The developers say that while the Java and C/C++ (used by Python and R) Arrow implementations will probably remain the most feature-rich, the Rust implementation is closing the feature gap quickly, and the 2.0 release includes a lot of improvements to the Rust implementation.
The Rust Arrow compute kernels have been improved with new kernels added for string operations, including substring, min, max, concat, and length. Many kernels have been improved to support dictionary-encoded arrays, and optimized for arrays without nulls, making them significantly faster in that case. The work on a Rust Parquet writer for Arrow data didn't make it into this release, and is now planned for the 3.0.0 release.
The Rust component has also seen work on DataFusion, the in-memory query engine with DataFrame and SQL APIs, built on top of base Arrow support. DataFusion now has a richer DataFrame API, and more scalable queries because of a change to use async/await with the tokio threaded runtime rather than launching dedicated threads.
DataFusion also has improved scalar function both in the SQL and the DataFrame API, including string length, COUNT(DISTINCT column, IsNotNullMin/Max for strings, Array of columns and string concatenation.
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|Last Updated ( Thursday, 29 October 2020 )|