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

Nathan Bossart <nathandbossart@gmail.com> writes:
> On Tue, Nov 19, 2024 at 02:33:27PM -0500, Tom Lane wrote:
>> I did think of a way that we could approximate encoding-correct
>> truncation here, relying on the fact that what's in pg_database
>> is encoding-correct according to somebody:
>> ...

> That's an interesting idea.  That code would probably need to live in
> GetDatabaseTuple(), but it seems doable.  We might be able to avoid the
> "mighty improbable" case by always truncating up to
> MAX_MULTIBYTE_CHAR_LEN-1 times and failing if there are multiple matches,
> too.

Hmm ... but with short characters (e.g. LATIN1) there might be
legitimately-different names that that rule would complain about.
Still, the workaround remains "so spell it like it is in the catalog".
On balance I think that's an improvement over what I was visualizing.

Also, we could bypass the multiple lookups unless both the
NAMEDATALEN-1'th and NAMEDATALEN-2'th bytes are non-ASCII, which
should be rare enough to make it not much of a performance issue.

One annoying point is that we also need this for role lookup.

            regards, tom lane