Re: BUG #11734: The "<<=" operator on "inet" values does not return the expected result.

michel@albert.lu writes:
> The best way to explain this is with a quick example script:

>     CREATE TABLE inettest (
>         value inet UNIQUE
>     );

>     INSERT INTO inettest VALUES
>         ('1.2.1.0/24'),
>         ('1.2.1.1/24'),
>         ('1.2.1.2/24'),
>         ('1.2.2.0/24'),
>         ('1.2.3.0/24'),
>         ('1.2.3.1/24'),
>         ('1.2.3.2/24'),
>         ('1.2.3.3/24'),
>         ('1.2.3.4/24')
>         ;

>     SELECT * FROM inettest WHERE value <<= '1.2.3.1/24'::inet;

> I would expect that the above select would only return *one* row. The one
> with the host '1.2.3.1/24'. Instead, it returns *all* rows of the
> '1.2.3.0/24' network.

The PG documentation is pretty clear on this point:

  The operators <<, <<=, >>, >>=, and && test for subnet inclusion. They
  consider only the network parts of the two addresses (ignoring any host
  part) and determine whether one network is identical to or a subnet of
  the other.
  [ first para in "Network Address Functions and Operators" ]

So <<= should return true for any two of the addresses you cite here.

Personally I'd use CIDR, not INET, for anything I was thinking of as a
network ID rather than a single host's ID.

            regards, tom lane