Re: v2 protocol: is it still used?

Guillaume Cottenceau <gc(at)mnc(dot)ch>:

> The only workaround I found back then,
> was to use protocol v2 (IIRC prepared statements are fully client
> side in protocol v2?). I noticed recently though that it's not
> going to be able anymore soon, because the 9.5 backend breaks on
> the driver passing autocommit=true anyways.
>

Workarounds exist for v3 as well: for instance, completely disable usage of
server-prepared statements.
Alternatively, we could even implement "use server-prepared statement at
most 5 times" (so the backend never switches to a generic plan).

I wonder what would be the best way to handle current
protocolVersion=2 installations:
1) ignore protocolVersion=2 and just use v3
2) throw exception "A connection could not be made using the requested
protocol 2"

Even though #1 might not be that expected, however I believe it will
provide smooth migration to never pgjdbc versions without "manual
configuration changes here and there"

Vladimir