CREATE OR REPLACE FUNCTION cleanup( _site int8, _upToDate date )
RETURNS INT AS $body$
    BEGIN
   
        DELETE FROM accesses
        WHERE req_time < _upToDate
        AND site = _site;

        ALTER TABLE accesses DROP CONSTRAINT accesses_request_fkey;
        ALTER TABLE accesses DROP CONSTRAINT accesses_search_fkey;
        ALTER TABLE accesses DROP CONSTRAINT accesses_referrer_fkey;

        DELETE FROM requests
        WHERE id NOT IN ( SELECT DISTINCT request FROM accesses );

        DELETE FROM search_referrals
        WHERE id NOT IN ( SELECT DISTINCT search FROM accesses );

        DELETE FROM referrers
        WHERE id NOT IN ( SELECT DISTINCT referrer FROM accesses );

        ALTER TABLE accesses
        ADD CONSTRAINT "accesses_request_fkey"
        FOREIGN KEY ( request )
        REFERENCES requests( id ) ON DELETE CASCADE;

        ALTER TABLE accesses
        ADD CONSTRAINT "accesses_search_fkey"
        FOREIGN KEY ( search )
        REFERENCES search_referrals( id ) ON DELETE SET NULL;

        ALTER TABLE accesses
        ADD CONSTRAINT "accesses_referrer_fkey"
        FOREIGN KEY ( referrer )
        REFERENCES referrers( id ) ON DELETE SET NULL;

        RETURN 0;
    END;
$body$ LANGUAGE plpgsql;