PostgreSQL 9.5.2 DELETE taking forever
Add a index to dependents tables (for eficient deletes)

If you have

create table "table"(
  id integer primary key,
  added_at date
);

create table other(
  other_id integer primary key,
  table_id integer,
  foreign key (table_id) references "table" (id)
);


and you delete rows from "table" postgres must search the other table for each row that you deletes in the "table". If you add an index in the other table postgres can search in the index.

CREATE INDEX ON other (table_id);


Now you can eficiently delete rows in "table".