Simple delete takes hours

Hi there,

I have a simple database:

CREATE TABLE pwd_description (  id SERIAL                NOT NULL UNIQUE PRIMARY KEY,  name varchar(50)         NOT
NULL
);

CREATE TABLE pwd_name (  id SERIAL                NOT NULL UNIQUE PRIMARY KEY,  description integer      NOT NULL
REFERENCESpwd_description(id),  name varchar(50)         NOT NULL,  added timestamp          DEFAULT now()
 
);

CREATE TABLE pwd_name_rev (  id SERIAL                NOT NULL UNIQUE PRIMARY KEY,  description integer      NOT NULL
REFERENCESpwd_description(id),  rev_of integer           NOT NULL REFERENCES pwd_name(id) ON DELETE 
 
CASCADE,  name varchar(50)         NOT NULL
);

The indexes shouldn't matter I think.

pwd_name_rev is filled by a stored procedure and a trigger (ON INSERT) 
when something is inserted to pwd_name. Both tables contain about 
4.500.000 emtries each.

I stopped 'delete from pwd_name where description=1' after about 8 hours 
(!). The query should delete about 500.000 records.
Then I tried 'delete from pwd_name_rev where description=1' - this took 
23 seconds (!).
Then I retried the delete on pwd_name but it's running for 6 hours now.

I use PostgreSQL 7.4.7 on Linux 2.6.10. The machine is a Celeron 2 GHz 
with 512 MB RAM.

PostgreSQL should do a full table scan I think, get all records with 
description=1 and remove them - I don't understand what's happening for >8 hours.


Any help is appreciated.


Thomas