Re: BUG #18711: Attempting a connection with a database name longer than 63 characters now fails

Hi,

On Fri, Nov 22, 2024 at 02:01:41PM -0600, Nathan Bossart wrote:
> On Fri, Nov 22, 2024 at 02:23:47PM -0500, Tom Lane wrote:
> > After more thought I don't really like the idea of failing if there
> > are multiple matches.  It means that we might fail in cases where
> > pre-v17 worked fine (because NAMEDATALEN-1 was accidentally the
> > right truncation point).  ISTM the entire point of this patch is to
> > restore the pre-v17 behavior as much as possible, so that seems like
> > the wrong outcome.
> 
> That's fine with me.

+1 

> > So that means we could do something like the attached.  (There's
> > room for argument about which error messages in InitPostgres
> > should use in_dbname versus the truncated name, but I chose to
> > use in_dbname for the two "does not exist" reports.)
> 
> Looks reasonable to me.  I had been thinking of ways to simplify this code
> based on Bruce's feedback, and I came up with the attached.  If nothing
> else, this at least helps minimize the amount of code that is only reached
> in extremely rare cases, but it's probably not quite as performant as v4
> for the usual path, so v4 may still be the way to go.

Yeah, so what about v6 attached ("mixing" v4 and v5 by using a fast path in
case the name is short enough).

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com