Finding the sequence used for a primary key, after renaming it

Hi.

I just ran into a problem when (/after) renaming a sequence.

It seems that psql does something different than DBD::Pg when finding
the default value of a column.

DBD::Pg seems to get it directly from pg_catalog.pg_attrdef(adsrc), but
apparantly 'ALTER SEQUENCE some_seq RENAME TO other_seq' doesn't update
that, and psql seems to look somewhere else.

Here is an example that hopefully illustrates the problem:

First I create a simple table and rename the sequence:

core@[local] test=# CREATE TABLE test (id serial, name text, value integer);
NOTICE: CREATE TABLE will create implicit sequence "test_id_seq" for serial column "test.id"
CREATE TABLE
core@[local] test=# \d test
Table "public.test"
Column | Type | Modifiers
--------+---------+---------------------------------------------------
id | integer | not null default nextval('test_id_seq'::regclass)
name | text |
value | integer |

core@[local] test=# ALTER SEQUENCE test_id_seq RENAME TO other_id_seq;
ALTER SEQUENCE
core@[local] test=# \d test
Table "public.test"
Column | Type | Modifiers
--------+---------+----------------------------------------------------
id | integer | not null default nextval('other_id_seq'::regclass)
name | text |
value | integer |

core@[local] test=#

This looks good, the default of the id column is automatically updated
with the new sequence name as expected.

For some reason pg_catalog.pg_attrdef(adsrc) isn't updated, though:

core@[local] test=# SELECT adrelid, adsrc FROM pg_catalog.pg_attrdef;
adrelid | adsrc
---------+----------------------------------
1466741 | nextval('test_id_seq'::regclass)
(1 row)

core@[local] test=#

When DBIx::Class asks DBD::Pg for the column_info, the COLUMN_DEF field
is filled in from the pg_attrdef:

$ perl -MDBI -e '$dbh=DBI->connect("dbi:Pg:dbname=test", "core", "core"); $info=$dbh->column_info(undef, undef, "test", "id")->fetchrow_hashref; print $info->{COLUMN_DEF} . "\n"'
nextval('test_id_seq'::regclass)
$

... and SELECT currval on 'test_id_seq' fails, as that isn't the name of
the sequence (any more).

My question is basically where to try and get it fixed:

* Should PostgreSQL update pg_attrdef as part of executing "ALTER
SEQUENCE .. RENAME TO .."?

* Should DBD::Pg get COLUMN_DEF from the same place that psql does? - or:

* Should DBIx::Class get the default value of a column from somewhere
else than COLUMN_DEF, if so, where?

Thanks :-)


Version information:

PostgreSQL 8.3.6
DBD::Pg 2.8.2
DBI 1.605
DBIx::Class 0.08010

Ubuntu 8.10 amd64


Best regards,

Adam