mysql 5.7 线程阻塞处理

出现的错误：

ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction

解决办法：

查看sleep的进程

mysql> show full processlist;
+-------+----------+-------------------+----------+---------+-------+----------+-----------------------------------------------------------------------------+
| Id    | User     | Host              | db       | Command | Time  | State    | Info                                                                        |
+-------+----------+-------------------+----------+---------+-------+----------+-----------------------------------------------------------------------------+
| 32579 | official | 127.0.0.1:42690   | official | Sleep   | 20926 |          | NULL                                                                        |
| 32715 | erp      | 127.0.0.1:2078    | NULL     | Sleep   |  4570 |          | NULL                                                                        |
| 32716 | erp      | 127.0.0.1:2079    | erp      | Sleep   |  3590 |          | NULL                                                                        |
| 32717 | erp      | 127.0.0.1:2080    | erp      | Sleep   |  3577 |          | NULL                                                                        |
| 32732 | erp      | 127.0.0.1:2081    | erp      | Sleep   |  3590 |          | NULL                                                                        |
| 32733 | erp      | 127.0.0.1:2082    | NULL     | Sleep   |  1412 |          | NULL                                                                        |
| 32734 | erp      | 127.0.0.1:2083    | erp      | Sleep   |  1160 |          | NULL                                                                        |
| 32735 | erp      | 127.0.0.1:2084    | erp      | Sleep   |   985 |          | NULL                                                                        |
| 32736 | erp      | 127.0.0.1:2085    | erp      | Sleep   |  1160 |          | NULL                                                                        |
| 32739 | erp      | 127.0.0.1:2088    | erp      | Sleep   |   695 |          | NULL                                                                        |
| 32740 | erp      | 127.0.0.1:2089    | erp      | Sleep   |   768 |          | NULL                                                                        |
| 32741 | erp      | 127.0.0.1:2090    | erp      | Sleep   |   688 |          | NULL                                                                        |
| 32742 | erp      | 127.0.0.1:2091    | erp      | Sleep   |   686 |          | NULL                                                                        |
| 32743 | erp      | 127.0.0.1:2092    | erp      | Sleep   |   687 |          | NULL                                                                        |
| 32745 | erp      | 127.0.0.1:2093    | erp      | Sleep   |   686 |          | NULL                                                                        |
| 32746 | erp      | 127.0.0.1:2094    | erp      | Sleep   |   686 |          | NULL                                                                        |
| 32763 | root     | localhost         | erp      | Query   |     0 | starting | show full processlist                                                       |
| 32765 | erp      | 127.0.0.1:58216   | erp      | Sleep   |    18 |          | NULL                                                                        |
| 32766 | erp      | 127.0.0.1:58218   | erp      | Sleep   |    41 |          | NULL                                                                        |
| 32767 | erp      | 127.0.0.1:58220   | erp      | Sleep   |    41 |          | NULL                                                                        |
| 32768 | erp      | 127.0.0.1:58222   | erp      | Sleep   |    41 |          | NULL                                                                        |
| 32769 | erp      | 127.0.0.1:58224   | erp      | Sleep   |     2 |          | NULL                                                                        |
| 32770 | erp      | 127.0.0.1:2106    | NULL     | Sleep   |   153 |          | NULL                                                                        |
| 32771 | erp      | 127.0.0.1:2107    | erp      | Sleep   |   148 |          | NULL                                                                        |
| 32772 | erp      | 127.0.0.1:2108    | erp      | Query   |    18 | updating | UPDATE `erp_user` SET `pwd`='OyUHgt21gTP2/5uFgbKZtq==' WHERE (`id`='10113') |
+-------+----------+-------------------+----------+---------+-------+----------+-----------------------------------------------------------------------------+

没有看到正在执行的慢SQL记录线程，再去查看innodb的事务表INNODB_TRX，看下里面是否有正在锁定的事务线程，看看ID是否在show full processlist里面的sleep线程中，如果是，就证明这个sleep的线程事务一直没有commit 或者 rollback而是卡住了，我们需要手动kill掉。

mysql> SELECT * FROM information_schema.INNODB_TRX\G;
*************************** 1. row ***************************
                    trx_id: 20342
                 trx_state: RUNNING
               trx_started: 2018-01-29 16:48:13
     trx_requested_lock_id: NULL
          trx_wait_started: NULL
                trx_weight: 4
       trx_mysql_thread_id: 32735
                 trx_query: NULL
       trx_operation_state: NULL
         trx_tables_in_use: 0
         trx_tables_locked: 1
          trx_lock_structs: 2
     trx_lock_memory_bytes: 1136
           trx_rows_locked: 1
         trx_rows_modified: 2
   trx_concurrency_tickets: 0
       trx_isolation_level: REPEATABLE READ
         trx_unique_checks: 1
    trx_foreign_key_checks: 1
trx_last_foreign_key_error: NULL
 trx_adaptive_hash_latched: 0
 trx_adaptive_hash_timeout: 10000
          trx_is_read_only: 0
trx_autocommit_non_locking: 0
1 row in set (0.00 sec)

ERROR: 
No query specified

看到有这条 32735 的sql，kill掉，执行kill 32735;

kill 32735;

然后再去查询INNODB_TRX表，就没有阻塞的事务sleep线程存在了，如下所示：

mysql> SELECT * FROM information_schema.INNODB_TRX\G;

Empty set (0.00 sec)

现在可以正常执行 sql 语句了