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 [EMAIL PROTECTED] www.ipinc.com