Re: pg_dump bug in 7.3.9 with sequences

>>create table foo (foo serial not null, bar text);
>>create sequence foo_seq;
>>alter table foo alter column foo set default nextval('foo_seq');
>>
>>
>
>This is flat out pilot error: you do not get to mess with the default
>expression of a SERIAL column, because it's part of the internal
>implementation of the SERIAL pseudo-type. If I were going to do
>anything about it, I'd patch ALTER TABLE to refuse the above command.
>
>
It is not pilot error if PostgreSQL allows it. There is
nothing "illegal" about the above commands in their execution.
The pg_dump application should recognize that the object has
changed and react accordingly.

Let me elaborate. Look at the following table (I didn't design it):

rp_nuke_old=# \d nuke_bbtopics
Table "public.nuke_bbtopics"
Column | Type | Modifiers
---------------------+----------------+---------------------------------------------------------------
topic_id | integer | not null default
nextval('public.nuke_bbtopics_id_seq'::text)
forum_id | smallint | not null default '0'
topic_title | character(255) | not null default ''
topic_poster | integer | not null default '0'
topic_time | integer | not null default '0'
topic_views | integer | not null default '0'
topic_replies | integer | not null default '0'
topic_status | smallint | not null default '0'
topic_vote | smallint | not null default '0'
topic_type | smallint | not null default '0'
topic_last_post_id | integer | not null default '0'
topic_first_post_id | integer | not null default '0'
topic_moved_id | integer | not null default '0'
news_id | integer | not null default '0'
Indexes: nuke_bbtopics_pkey primary key btree (topic_id),
forum_id_nuke_bbtopics btree (forum_id),
nuke_bbtopics_news_id btree (news_id),
topic_last_post_id_nuke_bbtopics btree (topic_last_post_id),
topic_type_nuke_bbtopics btree (topic_type),
topic_vote_nuke_bbtopics btree (topic_vote)
Check constraints: "$1" (forum_id >= 0)
"$2" (topic_views >= 0)
"$3" (topic_replies >= 0)
"$4" (topic_last_post_id >= 0)
"$5" (topic_first_post_id >= 0)
"$6" (topic_moved_id >= 0)

Notice that topic_id is an integer with a default value of:
nextval('public.nuke_bbtopics_id_seq'::text) .
Now lets look at what pg_dump does to this table:

CREATE TABLE nuke_bbtopics (
topic_id serial NOT NULL,
forum_id smallint DEFAULT '0' NOT NULL,
topic_title character(255) DEFAULT '' NOT NULL,
topic_poster integer DEFAULT '0' NOT NULL,
topic_time integer DEFAULT '0' NOT NULL,
topic_views integer DEFAULT '0' NOT NULL,
topic_replies integer DEFAULT '0' NOT NULL,
topic_status smallint DEFAULT '0' NOT NULL,
topic_vote smallint DEFAULT '0' NOT NULL,
topic_type smallint DEFAULT '0' NOT NULL,
topic_last_post_id integer DEFAULT '0' NOT NULL,
topic_first_post_id integer DEFAULT '0' NOT NULL,
topic_moved_id integer DEFAULT '0' NOT NULL,
news_id integer DEFAULT '0' NOT NULL,
CONSTRAINT "$1" CHECK ((forum_id >= 0)),
CONSTRAINT "$2" CHECK ((topic_views >= 0)),
CONSTRAINT "$3" CHECK ((topic_replies >= 0)),
CONSTRAINT "$4" CHECK ((topic_last_post_id >= 0)),
CONSTRAINT "$5" CHECK ((topic_first_post_id >= 0)),
CONSTRAINT "$6" CHECK ((topic_moved_id >= 0))
);

Notice that pg_dump has changed the topic_id integer to the serial
psuedotype. Which when restored will create:

Table "public.nuke_bbtopics"
Column | Type |
Modifiers
---------------------+----------------+---------------------------------------------------------------------
topic_id | integer | not null default
nextval('public.nuke_bbtopics_topic_id_seq'::text)
forum_id | smallint | not null default '0'
topic_title | character(255) | not null default ''
topic_poster | integer | not null default '0'
topic_time | integer | not null default '0'
topic_views | integer | not null default '0'
topic_replies | integer | not null default '0'
topic_status | smallint | not null default '0'
topic_vote | smallint | not null default '0'
topic_type | smallint | not null default '0'
topic_last_post_id | integer | not null default '0'
topic_first_post_id | integer | not null default '0'
topic_moved_id | integer | not null default '0'
news_id | integer | not null default '0'
Check constraints: "$1" (forum_id >= 0)
"$2" (topic_views >= 0)
"$3" (topic_replies >= 0)
"$4" (topic_last_post_id >= 0)
"$5" (topic_first_post_id >= 0)
"$6" (topic_moved_id >= 0)

So in the end I have a table with a column topic_id that is an integer
that points to the WRONG sequence.

Sincerely,

Joshua D. Drake

> regards, tom lane
>
>

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