CREATE TABLE IF NOT EXISTS t1 (a BYTEA NOT NULL,
                               r_pointer BIGINT,
                               s_pointer BIGINT,
                               data BYTEA,
                              PRIMARY KEY(a, r_pointer ))
                              PARTITION BY HASH (a);

SELECT * FROM t1 WHERE a ='xaaa' order by r_pointer desc limit 1;

SELECT * FROM t1 WHERE a =ANY ('{xaaa,xbbbb}'::bytea[])
order by r_pointer desc;