I think so - I wrote my own Rust FFI bindings for SQLite extensions, and I tried to make it as fast as possible, but a "hello world" extension was still 10-15% slower in Rust than C[0].

That being said, it depends what the extension does - a "hello world" extension mainly just calls the same SQLite C APIs over and over again, so the small Rust layer makes it a bit slower. However, my Rust extensions for regex[1] and CSV parsing[2] are usually faster than the C counterparts, mostly due to less memory allocations and batching. It's not a 1:1 comparison (both extensions have slightly different APIs and features), but I'd say a lot of "real world" features available in Rust can be faster than what's available in C.

That being said, I'm sure someone could write their own faster CSV or regex extension in C that is faster than the Rust ones. But it's a ton of work to do that from scratch, and I find wrapping a pre-existing Rust implementation to be much easier

[0] https://github.com/asg017/sqlite-loadable-rs?tab=readme-ov-f... [1] https://github.com/asg017/sqlite-regex [2] https://github.com/asg017/sqlite-xsv

First, Rust compiled is not wt that performant. Well behind c, go, c++,...

But also because SQLite is based on crazily optimized C!