[ngalstyan4]

My understanding is Trusted Language Extensions refer to extensions written in PL/Rust - a Postgres extension mechanism to write user defined functions and use them in SQL queries.

PL/Rust is a more performant and more feature-rich alternative to PL/pgSQL, which is the traditional UDF scripting language for Postgres.

Building a vector index (or any index for that matter) inside Postgres is a more involved process and can not be done via the UDF interface, be it Rust, C or PL/pgSQL.

So, I think even if Lantern was written in Rust, it would not be a Trusted Language Extension under this definition.

[kiwicopple]

(disclosure, i work at supabase and have been developing TLEs with the RDS team)

Trusted Language Extensions refer to an extension written in any trusted language. In this case Rust, but it also includes: plpgsql, plv8, etc. See [0]

> PL/Rust is a more performant and more feature-rich alternative to PL/pgSQL

This is only partially true. plpgsql has bindings to low-level Postgres APIs, so in some cases it is just as fast (or faster) than Rust.

> Building a vector index (or any index for that matter) inside Postgres is a more involved process and can not be done via the UDF interface, be it Rust, C or PL/pgSQL

Most PG Rust extensions are written with the excellent pgrx framework [1]. While it doesn't have index bindings right now, I can certainly imagine a future where this is possible[2].

All that said - I think there are a lot of hoops to jump through right now and I doubt it's worth it for your team. I think you are right to focus on developing a separate C extension

[0] TLE: https://supabase.com/blog/pg-tle

[1] pgrx: https://github.com/pgcentralfoundation/pgrx

[2] https://github.com/pgcentralfoundation/pgrx/issues/190#issue...