Postgres driver ignores .persistent(false)

[nk9]

Bug Description

It is not presently possible to turn off the Postgres driver's use of named prepared statements. This is a blocker for users whose database doesn't support these. For example, Supabase has introduced a new pooler for all hosted instances which doesn't presently support saving these statements, so sqlx no longer works with that service.

I discovered this sqlx limitation via Discord. In a thread there, @abonander said:

The real issue is that the Postgres driver always uses named prepared statements, even if you set .persistent(false)

It doesn't have to, that's just how it's currently written.

Minimal Reproduction

I don't know how to provide this given that my reproduction steps involve using the Supabase hosted service with credentials and whatnot. However, the issue is independent of that.

Info

• SQLx version: 0.7.3
• SQLx features enabled: ["runtime-tokio-rustls", "json"]
• Database server and version: Postgres 15.1 (Supabase hosted)
• Operating system: macOS Sonoma 14.1.2
• rustc --version: rustc 1.77.1 (7cf61ebde 2024-03-27)

[abonander]

It's not that it ignores the flag, strictly speaking. It does as it says on the tin: it won't retain the prepared statement after execution.

The problem is that it always prepares the statement with an explicit name because it uses the same code path for both cases.

[nk9]

Is this something that a newish Rust programmer would have a chance implementing? Is it just about using a random statement name each time when the persistent flag is set to false? If it's not too complex a solution, I'd appreciate a pointer to where to make the change.

[nk9]

Is this where the code is? Any pointers on what needs to change? I'm assuming it has something to do with get_or_prepare_statement…

If I can fork sqlx and make a change, just so I can get my little project working, that would be fantastic.

[ClasicRando]

@nk9 I think you meant to reference here because that's where the postgres driver does a similar action as to what you linked in the MySQL driver