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' OR query = 'SELECT ? AS dummy;');
 count 
-------
     1
(1 row)

SELECT reads, reads_blks, writes, writes_blks FROM pg_stat_kcache_detail WHERE datname = current_database() AND (query = 'SELECT $1 AS dummy' OR query = 'SELECT ? AS dummy;');
 reads | reads_blks | writes | writes_blks 
-------+------------+--------+-------------
     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 LIKE 'SELECT count(*) FROM test%';
 cpu_time_ok 
-------------
 t
(1 row)