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Message-ID: <46E154D2.8040203@gmail.com>
Date: Fri, 07 Sep 2007 17:40:34 +0400
From: Aleksandr Vinokurov <aleksandr.vin@gmail.com>
User-Agent: Thunderbird 2.0.0.6 (Windows/20070728)
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To: pgsql-sql@postgresql.org
Subject: SERIAL type's sequence is double-called or ?
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Hello all,

I have a question with the SERIAL type. I want to use it for default 
identification of table entries:

create table chuwee (
   num serial primary key,
   mesg varchar(50) not null
);

And all the inserts to this table I'm gonna log to this table:

create table chuwee_log (
   id serial primary key,
   date timestamp default current_timestamp,
   num integer not null,
   mesg varchar(50) not null
);

Logging will be done with this rule:

create or replace rule chuwee_rule as on insert to chuwee
do insert into chuwee_log (num, mesg)
    values (new.num, new.mesg);


And all seems to work, but a sequence is called twice for inserts, and 
logged "num"-s get a +1 value:

sunline=# insert into chuwee (mesg) values ('Hello, world!');
INSERT 9596671 1
sunline=# insert into chuwee (mesg) values ('Aquarium full of tequilla');
INSERT 9596673 1
sunline=# select * from chuwee_log;
  id |            date            | num |           mesg
----+----------------------------+-----+---------------------------
   1 | 2007-09-08 16:18:26.707384 |   2 | Hello, world!
   2 | 2007-09-08 16:18:58.711599 |   4 | Aquarium full of tequilla
(2 rows)

sunline=# select * from chuwee;
  num |           mesg
-----+---------------------------
    1 | Hello, world!
    3 | Aquarium full of tequilla
(2 rows)


How it can be cured, if any?

Best dishes,
Aleksandr.