From: "Dan Langille" <dan@langille.org>
To: pgsql-sql@postgresql.org
Date: Fri, 04 Jul 2003 20:08:04 -0400
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Subject: inet versus text for ip addresses
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The PostgreSQL inet datatype stores an holds an IP host address, and 
optionally the identity of the subnet it is in, all in one field.  
This requires 12 bytes.   

Using my "random" data of approximately 8000 IP addresses collected 
during previous polls, I've found the average length of an IP address 
is 13.1 bytes.    An integer requires 4 bytes.

First question: Why not store an option to store just an IP address?  
That should require less than the 12 bytes for inet.

On to the real question:

The existing tables are:

create table recount_ips
(
    ipid        serial                not null,
    ipaddress   inet                  not null,
    primary key (ipid)
);

create unique index recount_ips_ip_address on recount_ips 
(ipaddress);

create table recount_iptopolls
(
    pollid      integer               not null,
    ipid        integer               not null,
    primary key (pollid, ipid)
);

alter table recount_iptopolls
    add foreign key  (pollid)
       references recount_polls (pollid) on update restrict on delete 
restrict;

alter table recount_iptopolls
    add foreign key  (ipid)
       references recount_ips (ipid) on update restrict on delete 
restrict;


I think a better solution is one table:

create table recount_iptopolls
(
    pollid      integer               not null,
    ipaddress   inet                  not null,
    primary key (pollid, ipaddress)
);

alter table recount_iptopolls
    add foreign key  (pollid)
       references recount_polls (pollid) on update restrict on delete 
restrict;

It removes a table and the associated primary key, and removed a 
foreign key from the modified recount_iptopolls table.

Comments?
-- 
Dan Langille : http://www.langille.org/