###一、錯誤演示

如下：

```
root@localhost:test:09:49:03>create table ttt(id int) engine=myisam ;
ERROR 1286 (42000): Unknown storage engine 'MyISAM'
```

###二、相關引數

- enforce_storage_engine：建表進行引擎檢查，是否滿足設定的引擎值。
- sql_mode（NO_ENGINE_SUBSTITUTION）：根據前面的檢查值進行綜合判斷，如果設定了NO_ENGINE_SUBSTITUTION則進行報錯，如果沒有設定則進行，且將新建表的引擎轉為enforce_storage_engine設定的引擎。

我們環境中設定enforce_storage_engine為Innodb，sql_mode中設定了NO_ENGINE_SUBSTITUTION。

###三、相關函式

- check_engine
- ->ha_enforce_handlerton

部分邏輯如下：

1. 根據ha_enforce_handlerton函式進行引擎檢查，主要檢查enforce_storage_engine引數設定的值是否為已知的引擎。否則報錯 Unknown storage engine ，返回值為enforce_storage_engine指定的引擎（比如Innodb）。
2. 根據上面的返回值進行判斷
- 如果建表指定的引擎（比如這裡的MyISAM）和enforce_storage_engine設定的引擎（比如這裡的Innodb）不同，同時sql_mode設定了NO_ENGINE_SUBSTITUTION。則報錯ERROR 1286 (42000): Unknown storage engine 'MyISAM'，這也是當前的報錯。
- 如果沒有設定sql_mode NO_ENGINE_SUBSTITUTION，那麼使用enforce_storage_engine指定的值代替建表語句的指定的引擎值（比如用Innodb代替MyISAM），同時報出警告，ER_WARN_USING_OTHER_HANDLER，輸出為新的引擎值。

###四、修改

登出掉enforce_storage_engine引數即可。

###五、棧

```
#0  check_engine (thd=0x7fffe400a8a0, db_name=0x7fffe40108f0 "test", table_name=0x7fffe4010328 "ttt", create_info=0x7fffe8ecd890, alter_info=0x7fffe8ecd300)
    at /cdh/mysqldebug/percona-server-5.7.29-32/sql/sql_table.cc:11318
#1  0x000000000155d81e in create_table_impl (thd=0x7fffe400a8a0, db=0x7fffe40108f0 "test", table_name=0x7fffe4010328 "ttt", error_table_name=0x7fffe4010328 "ttt", 
    path=0x7fffe8eccf60 "./test/ttt", create_info=0x7fffe8ecd890, alter_info=0x7fffe8ecd300, internal_tmp_table=false, select_field_count=0, no_ha_table=false, is_trans=0x7fffe8ecd1ee, 
    key_info=0x7fffe8ecd170, key_count=0x7fffe8ecd16c) at /cdh/mysqldebug/percona-server-5.7.29-32/sql/sql_table.cc:5138
#2  0x000000000155f352 in mysql_create_table_no_lock (thd=0x7fffe400a8a0, db=0x7fffe40108f0 "test", table_name=0x7fffe4010328 "ttt", create_info=0x7fffe8ecd890, alter_info=0x7fffe8ecd300, 
    select_field_count=0, is_trans=0x7fffe8ecd1ee) at /cdh/mysqldebug/percona-server-5.7.29-32/sql/sql_table.cc:5753
#3  0x000000000155f47a in mysql_create_table (thd=0x7fffe400a8a0, create_table=0x7fffe4010368, create_info=0x7fffe8ecd890, alter_info=0x7fffe8ecd300)
    at /cdh/mysqldebug/percona-server-5.7.29-32/sql/sql_table.cc:5801
#4  0x00000000014cc36d in mysql_execute_command (thd=0x7fffe400a8a0, first_level=true) at /cdh/mysqldebug/percona-server-5.7.29-32/sql/sql_parse.cc:3510
#5  0x00000000014d2e1b in mysql_parse (thd=0x7fffe400a8a0, parser_state=0x7fffe8ece4a0, update_userstat=false) at /cdh/mysqldebug/percona-server-5.7.29-32/sql/sql_parse.cc:5927
#6  0x00000000014c7a55 in dispatch_command (thd=0x7fffe400a8a0, com_data=0x7fffe8ecec90, command=COM_QUERY) at /cdh/mysqldebug/percona-server-5.7.29-32/sql/sql_parse.cc:1539
#7  0x00000000014c688a in do_command (thd=0x7fffe400a8a0) at /cdh/mysqldebug/percona-server-5.7.29-32/sql/sql_parse.cc:1060
#8  0x00000000015fab28 in handle_connection (arg=0x3c4f150) at /cdh/mysqldebug/percona-server-5.7.29-32/sql/conn_handler/connection_handler_per_thread.cc:325
#9  0x00000000018cad34 in pfs_spawn_thread (arg=0x3c568b0) at /cdh/mysqldebug/percona-server-5.7.29-32/storage/perfschema/pfs.cc:2198
#10 0x00007ffff7bc6e65 in start_thread () from /lib64/libpthread.so.0
#11 0x00007ffff5fa088d in clone () from /lib64/libc.so.6
```

MySQL：ERROR 1286 (42000): Unknown storage engine 'MyISAM'

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