> DELETE FROM table1 WHERE table2_id = ?
For bulk deletes, try :
DELETE FROM table1 WHERE table2_id IN (list of a few thousands ids)
- or use a JOIN delete with a virtual VALUES table
- or fill a temp table with ids and use a JOIN DELETE
This will save cliet/server roundtrips.
Now, something that can make a DELETE very slow is a non-indexed ON DELETE
CASCADE foreign key : when you DELETE FROM table1 and it cascades to a
DELETE on table2, and you forget the index on table2. Also check the time
spent in triggers. Do you have a GIN index ?