text: CREATE TABLE t2 (
      a   int,
      b   int
  );
  
  INSERT INTO t2 SELECT mod(i,100), mod(i,100)
                   FROM generate_series(1,1000000) s(i);
  
  CREATE STATISTICS s2 (mcv) ON a, b FROM t2;
  
  ANALYZE t2;
  
  -- valid combination (found in MCV)
  EXPLAIN ANALYZE SELECT * FROM t2 WHERE (a = 1) AND (b = 1);
  
  -- invalid combination (not found in MCV)
  EXPLAIN ANALYZE SELECT * FROM t2 WHERE (a = 1) AND (b = 2);
  