Workflow

1. A session connects and creates the table t1 and inserts one record.

    CREATE TABLE t1 (col1 INT, col2 INT, col3 INT, col4 TEXT) ENGINE = InnoDB ;

    ALTER TABLE t1 ADD PRIMARY KEY ( col4(10), col2 ) ;

    INSERT INTO t1 (col2,col4) VALUES(2, 'Sooo inportant data');

    Mode is auto commit.

2. The same session runs random

     ALTER TABLE t1 FORCE         or

     ALTER TABLE t1 ADD COLUMN extra INT; ALTER TABLE t1 DROP COLUMN col3 ; ALTER TABLE t1 CHANGE COLUMN extra col3 INT ;

3. At some point of time the server process gets killed (SIGKILL).

4. The server gets restartet.

5. Now

     SHOW KEYS FROM `test`.`t1` harvests

    1932: Table 'test.t1' doesn't exist in engine.