CREATE FUNCTION get_graph_data(boolean) RETURNS SETOF cake.user_graph AS '
declare
do_delete alias for $1;
now_day timestamp;
csess cake.session;
ugraph cake.user_graph;
begin
 -- текуйщий день
 now_day = CURRENT_DATE;

 --закрытые сессии
 select into csess * from session where s_end is not null;
 
 for ugraph in SELECT u.login,extract(epoch from k.kdatetime,k.diff_in,k.diff_out FROM keepalive k, users u, session s WHERE k.id_session in csess.id and s.id_user=u.id and k.kdatetime<now_day order by u.login,k.kdatetime 
loop
 return next ugraph;
end loop;
return ugraph;
end
'
LANGUAGE plpgsql;

CREATE TYPE user_graph AS (
        login character( 20 ),
        datetime double precision,
        diff_in bigint,
        diff_out bigint 
);

CREATE TABLE keepalive (
    id serial NOT NULL,
    id_session integer NOT NULL,
    kdatetime timestamp without time zone DEFAULT ('now'::text)::timestamp( 6 ) with time zone NOT NULL,
    volumein bigint DEFAULT  0  NOT NULL,
    volumeout bigint DEFAULT  0  NOT NULL,
    diff_in bigint DEFAULT  0 ,
    diff_out bigint DEFAULT  0 
) WITHOUT OIDS;