Re: Add ParameterDescription message to libpq frontend long message types

On 01/04/2026 09:32, Ning Sun wrote:
> I'm maintaining a Rust library pgwire to implement postgres wire 
> protocol in rust. While doing a corner case test, I noticed the 
> inconsistency for ParameterDescription between backend and frontend.
> 
> The backend allows up to 65535 parameters in a prepared statement. But 
> when running Describe on the statement, there is a size limit of 30000 
> bytes for ParameterDescription on the frontend. This means we can only 
> describe statements with at most ~7500 parameters. For statements exceed 
> the limit, it ends up with error about the message size.
> 
> This patch simply adds ParameterDescription to VALID_LONG_MESSAGE_TYPE 
> whitelist to remove the cap.

Committed and backpatched to all supported versions, thanks!

- Heikki