CREATE EXTENSION pg_stat_statements;
CREATE EXTENSION pg_stat_kcache;
-- dummy query
SELECT 1 AS dummy;
 dummy 
-------
     1
(1 row)

SELECT count(*) FROM pg_stat_kcache WHERE datname = current_database();
 count 
-------
     1
(1 row)

SELECT count(*) FROM pg_stat_kcache_detail WHERE datname = current_database() AND query = 'SELECT $1 AS dummy';
 count 
-------
     1
(1 row)

SELECT query, reads, reads_blks, writes, writes_blks FROM pg_stat_kcache_detail WHERE datname = current_database() AND query = 'SELECT $1 AS dummy';
       query        | reads | reads_blks | writes | writes_blks 
--------------------+-------+------------+--------+-------------
 SELECT $1 AS dummy |     0 |          0 |      0 |           0
(1 row)

-- dummy table
CREATE TABLE test AS SELECT i FROM generate_series(1, 1000) i;
-- dummy query again
SELECT count(*) FROM test;
 count 
-------
  1000
(1 row)

SELECT user_time + system_time > 0 AS cpu_time_ok FROM pg_stat_kcache_detail WHERE datname = current_database() AND query = 'SELECT count(*) FROM test';
 cpu_time_ok 
-------------
 t
(1 row)