Seems like a good time to recommend Apache Datafusion. It's designed to be a library, but works pretty well standalone as well. There's a CLI version, but also Python and Java bindings, as well as a Rust library, of course.
From my own experience I can say it integrates far better into your Rust app than DuckDB does.
they don't say "this fall", they say later this year, I think it is some parallel effort, and it is actually going for few years already (rewriting index logic to have them in mmapped buffers and not in memory), finger crossed they will finish it finally.
No, it's a competing ecosystem, even though both are built on Apache Arrow, and their dataframe APIs might look similar on the surface.
DataFusion is being used as a building block for a growing number of databases and data processing engines in Rust, as it offers the necessary primitives.
From my own experience I can say it integrates far better into your Rust app than DuckDB does.
Well over 100 monthly contributors, too.