Re: SQL access to database attributes

Vik Fearing <vik(dot)fearing(at)dalibo(dot)com> writes:
> On 06/21/2014 10:11 PM, Pavel Stehule wrote:
>> Is any reason or is acceptable incompatible change CONNECTION_LIMIT
>> instead CONNECTION LIMIT? Is decreasing parser size about 1% good enough
>> for breaking compatibility?

> How is compatibility broken? The grammar still accepts the old way, I
> just changed the documentation to promote the new way.

While I agree that this patch wouldn't break backwards compatibility,
I don't really see what the argument is for changing the recommended
spelling of the command.

The difficulty with doing what you've done here is that it creates
unnecessary cross-version incompatibilities; for example a 9.5 psql
being used against a 9.4 server would tab-complete the wrong spelling
of the option. Back-patching would change the set of versions for
which the problem exists, but it wouldn't remove the problem altogether.
And in fact it'd add new problems, e.g. pg_dumpall output from a 9.3.5
pg_dumpall failing to load into a 9.3.4 server. This is not the kind of
change we customarily back-patch anyway.

So personally I'd have just made connection_limit be an undocumented
internal equivalent for CONNECTION LIMIT, and kept the latter as the
preferred spelling, with no client-side changes.

regards, tom lane