Re: DELETE SQL too slow.

On Tue, 3 Sep 2002, Diogo Biazus wrote:

> I'm having problems with delete commands in postgres. They are too slow.
> I'm trying to delete a set o 300 rows in table with 50000 rows with a
> simple command like:
>
> DELETE FROM table WHERE field1 = '4'
>
> When I run the explain it tells me that index_scan is being used. But to
> complete the delete it takes more than 30 minutes and the CPU use never
> rise above 10%. The server that runs postgres is a RedHat Linux 7.3 over
> a Pentium III 900 Mhz with 512 MB RAM

Are you sure that there isn't a foreign key referencing this table?
That'll cascade out to at least a bunch of selects, and if you have
an on delete action, that'll change the other table(s) and possibly
then any table that references that one.