foreign key take too much time to check

Hi, there,

I want add a constraint to my tables:
I have 2 tables:
1. Table_A(id int 4 primary key, item text, ......),
2. Table_B(id int4, cid int4, constraint b_fk foreign key (id)
refereneces Table_A(id)
on delete cascade on update cascade);
Table_A has ~900,000 rows,
Table_B has ~1,200,000 rows.
I tried serveral ways to generate the b_fk
1. alter table add constraint b_fk foreign key (id) refereneces
Table_A(id)
on delete cascade on update cascade,
2. pg_dump -d -t Table_B -f B dbname, then psql dbname < B
even before that , I create an index for id of Table_B, and vacuum table
Table_A and Table_B,

insert (check) speed is very slow, ~100 rows per minute, for my table
has ~1.2M rows will
take more than 200hours, I wonder to compare 2 integers why takes so
long, if no b_fk , the Table_B
can be reload in 5 minutes...

Is anybody know how reslove this problem? I 'll appreciate.

--
Jie LIANG

Internet Products Inc.

10350 Science Center Drive
Suite 100, San Diego, CA 92121
Office:(858)320-4873

jliang(at)ipinc(dot)com
www.ipinc.com