DROP TABLE IF EXISTS a CASCADE;
DROP STATISTICS IF EXISTS aestat;

CREATE TABLE a AS (
	SELECT
		gs % 10 AS x,
		(gs % 10 + (gs/10::int4) % 10) % 10 AS y,
		(gs / 100)::int4 AS z
	FROM generate_series(1,1000) AS gs
);
INSERT INTO a (SELECT gs,gs,gs FROM generate_series(1000,2000) AS gs);

-- ALTER TABLE a ADD PRIMARY KEY (x,y,z);
-- CREATE INDEX ON a(x);
ANALYZE a;

EXPLAIN SELECT * FROM a WHERE x=1 AND y=1 AND z=1;

CREATE STATISTICS aestat(dependencies,ndistinct) ON x,y,z FROM a;
ANALYZE a;

EXPLAIN SELECT * FROM a WHERE x=1 AND y=1 AND z=1;