Failed to match the stats from replay context with the optimizer stats:

set optimizer_record_context=ON;

create table t1 (btn char(10) not null, key using HASH (btn)) engine=heap;

insert into t1 values ("hello"),("hello"),("hello"),("hello"),("hello"),("a"),("b"),("c"),("d"),("e"),("f"),("g"),("h"),("i");

alter table t1 add column new_col char(1) not null, add key using HASH (btn,new_col), drop key btn;

update t1 set new_col=left(btn,1);

explain select * from t1 where btn="a";

SELECT context INTO DUMPFILE 'context1.txt' FROM INFORMATION_SCHEMA.OPTIMIZER_CONTEXT;

source /home/ppandith/test2/bld/data2/m8/context1.txt

+------+-------------+-------+------+---------------+------+---------+------+------+-------------+

| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+------+-------------+-------+------+---------------+------+---------+------+------+-------------+

|    1 | SIMPLE      | t1    | ALL  | btn           | NULL | NULL    | NULL | 14   | Using where |

+------+-------------+-------+------+---------------+------+---------+------+------+-------------+

+------+-------------+-------+------+---------------+------+---------+------+------+-------------+

| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+------+-------------+-------+------+---------------+------+---------+------+------+-------------+

|    1 | SIMPLE      | t1    | ALL  | btn           | NULL | NULL    | NULL | 14   | Using where |

+------+-------------+-------+------+---------------+------+---------+------+------+-------------+

1 row in set, 1 warning (0.001 sec)

MariaDB [m8]> show warnings;

+---------+------+---------------------------------------------------------------------------------------------------------------------------+

| Level   | Code | Message                                                                                                                   |

+---------+------+---------------------------------------------------------------------------------------------------------------------------+

| Warning | 4254 | Failed to match the stats from replay context with the optimizer stats: m8.t1.btn doesn't exist in list of range contexts |

+---------+------+---------------------------------------------------------------------------------------------------------------------------+