We are excited to introduce Aisle: a lightweight Parquet query library that delivers efficient predicate pushdown for reading Parquet files. Aisle's binary size is only about one-fifth of the DataFusion Parquet datasource, making it compact and easy to embed.

Rust's asynchronous disk I/O efficiency is critically important to us because we're building a database called Tonbo in async Rust—a tiered-storage database that uses memory, disk, and object storage layers on top of the Parquet format. However, as many in the community have observed, async Rust's disk I/O is not always ideal, largely because fully asynchronous file I/O APIs are still relatively new on most mainstream operating systems.

Multi-threading is a cornerstone of modern programming, enabling applications to handle multiple tasks simultaneously. While web browsers support concurrency through the Web Workers API, WebAssembly (Wasm) still lacks built-in thread support. Currently, threading in Wasm is part of an active proposal in Phase 4 (standardizing the feature), as detailed in the WebAssembly specificcation.

Barbara had a lot of experience developing web services with async Rust. One day, she read a blog about io_uring, which described it as the next-generation async I/O interface for Linux. Interested, Barbara decided to try it out in her sidecar web service...