Re: inet increment w/ int8

From: Bruno Wolff III
Subject: Re: inet increment w/ int8
Date: ,
Msg-id: 20050420151810.GA512@wolff.to
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In response to: Re: inet increment w/ int8  ("Ilya A. Kovalenko")
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inet increment w/ int8  ("Ilya A. Kovalenko", )
 Re: inet increment w/ int8  ("Ilya A. Kovalenko", )
 Re: inet increment w/ int8  (Bruce Momjian, )
  Re: inet increment w/ int8  ("Ilya A. Kovalenko", )
   Re: inet increment w/ int8  (Bruce Momjian, )
    Re: inet increment w/ int8  (Greg Stark, )
     Re: inet increment w/ int8  (Bruce Momjian, )
      Re: inet increment w/ int8  (Greg Stark, )
       Re: inet increment w/ int8  ("Ilya A. Kovalenko", )
        Re: inet increment w/ int8  (Bruno Wolff III, )
      Re: inet increment w/ int8  ("Ilya A. Kovalenko", )
    Re: inet increment w/ int8  (Bruno Wolff III, )
  Re: inet increment w/ int8  (Patrick Welche, )
 Re: inet increment w/ int8  (Bruce Momjian, )
  Re: inet increment w/ int8  (Douglas McNaught, )
   Re: inet increment w/ int8  (Bruce Momjian, )
    Re: inet increment w/ int8  (Stephen Frost, )
    Re: inet increment w/ int8  ("Sander Steffann", )

On Wed, Apr 20, 2005 at 12:30:08 +0800, "Ilya A. Kovalenko" <> wrote:
> GS> I see a use case for of generating addresses based on a sequence or some
> GS> primary key from the database.
> 
> GS> Something like
> 
> GS> CREATE SEQUENCE hosts_ip_seq MAXVALUE 65536;
> GS> ALTER TABLE hosts ALTER ip SET DEFAULT '10.0.0.0/16'::inet + nextval(hosts_ip_seq')
> 
> hmm, not quite good idea - SEQUENCEs, by design, does not rollback next
> value on transation rollback, so you'll have holes on address range when
> other values will break some constraints or concurrent sessions
> appears.

You are going to have to have some way of handling holes anyway. What
happens when an allocated IP address is returned? That is why I think
for most uses a table with a row for each possible allocation is the
way to go.



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