text: drop if exists t;
  CREATE TABLE t (col1 INT, col2 INT, col3 INT);
  CREATE INDEX i_t_col1_col2_col3 ON t (col1,col2,col3);
  INSERT INTO t VALUES (1,2,3),(4,5,6),(10,8,9);
  SELECT * FROM t WHERE col1 < 6 limit 1-1-1-1-1-1-1-1-1-1-1+100000000;
  SELECT * FROM t WHERE col1 < 6 using index i_t_col1_col2_col3  keylimit 1-1-1-1-1-1-1-1-1-1-1+100000000;
  SELECT * FROM t WHERE col1 < 6 using index i_t_col1_col2_col3  keylimit 0,1-1-1-1-1-1-1-1-1-1-1+100000000;
  SELECT * FROM t WHERE col1 < 6 using index i_t_col1_col2_col3  keylimit 1,1-1-1-1-1-1-1-1-1-1-1+100000000; 
  
  CREATE INDEX i_t_col1_col2 ON t (col1,col2);
  SELECT * FROM t WHERE col1< 6 order by col1,col2 limit 1-1-1-1-1-1-1-1-1-1-1+100000000;
  SELECT * FROM t WHERE col1< 6 order by col1,col2;
  SELECT * FROM t WHERE col1< 6 order by col1,col2 limit 0,2;
  drop if exists t;