Re: [HACKERS] New IP address datatype

> Thus spake Tom Lane
> > > Thus spake Mark Volpe
> > >> Hosts are specified as '134.67.131.10' or '134.67.131.10/32' and
> > >> display 134.67.131.10.
> > 
> > Hmm.  This suggests that the example given in the recent discussion
> > about primary keys is bogus: 198.68.123.0/24 is never equal to
> > 198.68.123.0/27, because they represent networks of different sizes.
> 
> I don't think it's so clear cut.  For INET, the two addresses refer
> to the same host but contradict each other in network details.  The
> INET type is primarily a host type with optional network information
> added.  One might even argue that 198.68.123.1/24 and 198.68.123.2/27
> should not be allowed to coexist but that's probably going too far.
> 
> For the CIDR type, they refer to two different networks but they overlap.
> The argument is that as a primary key they partially conflict so they
> shouldn't be allowed to coexist.
> 
> > If you were talking about host addresses, then the netmask would be
> > /32 in both cases, and so the issue doesn't arise.
> 
> Right.  For the INET type the netbits defaults to /32 so it can be used
> for hosts transparently.
> 
> > I'm back to the opinion that netmask does matter in comparisons and in
> > indexes ... but I'd sure like to hear what Vixie has to say about it.
> 
> I have asked him.
> 
> > BTW, if we did want to make INET and CIDR have different behavior in
> > comparisons and indexes, that would mean having two sets of operators
> > listed in the system catalogs.  We cannot add that as a post-6.5 patch
> > because it would require an initdb, which is one of the things we don't
> > do between major releases.  If it's wrong (I'm not convinced) we must
> > either fix it this week or live with it till 6.6 ...
> 
> At this point I doubt we want to start mucking with catalogues and new
> operators.  Fixing it to be consistent is probably doable.
> 
> And since I will never use either type as a primary key, I can live
> with either decision.  :-)

OK, but let's make a decision.

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