mysql怎么杀线程 如何杀线程

MYSQL中如何强制终止一条语句的执行?

KILL命令的语法格式如下:KILL [CONNECTION | QUERY] thread_id

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步骤如下:

1、KILL允许自选的CONNECTION或QUERY修改符:KILL CONNECTION与不含修改符的KILL一样:它会终止与给定的thread_id有关的连接。

2、KILL QUERY会终止连接当前正在执行的语句,但是会保持连接的原状。

3、如果您拥有PROCESS权限,则您可以查看所有线程。

4、如果您拥有超级管理员权限,您可以终止所有线程和语句。否则,您只能查看和终止您自己的线程和语句。

5、您也可以使用mysqladmin processlist和mysqladmin kill命令来检查和终止线程。

首先登录mysql,然后使用: show processlist; 查看当前mysql中各个线程状态。

以上显示出当前正在执行的sql语句列表,找到消耗资源最大的那条语句对应的id.

然后运行kill命令,命令格式如下:

[sql] view plain copy

kill id;

- 示例:

kill 8358

杀掉即可。

如何关闭电脑中关于mysql的相关线程

数据库为了及时响应请求,一定会保持一定数目的

线程,哪怕暂时不用。

你在

client

调用

close

释放了连接,那么你工作就已经完成了。

想确定会不会有问题,那么可以这么做。

不停的重新运行你的这段代码,如果

mysql

的线程数

没有增多

就不是问题。

如果随运行次数

线性增加,再来考虑解决这个问题

就是这样的,线程的回收,mysql

有自己的机制。你写程序的时候,最好也这么做,资源的回收不是越快越好,因为初始化资源也是要消耗代价的。

如何 查找 mysql 中如何 kill 引起死锁的线程id

如果遇到死锁了,怎么解决呢?找到原始的锁ID,然后KILL掉一直持有的那个线程就可以了, 但是众多线程,可怎么找到引起死锁的线程ID呢? MySQL 发展到现在,已经非常强大了,这个问题很好解决。 直接从数据字典连查找。

我们来演示下。

线程A,我们用来锁定某些记录,假设这个线程一直没提交,或者忘掉提交了。 那么就一直存在,但是数据里面显示的只是SLEEP状态。

mysql set @@autocommit=0;

Query OK, 0 rows affected (0.00 sec)

mysql use test;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

mysql show tables;

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

| Tables_in_test |

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

| demo_test |

| t3 |

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

2 rows in set (0.00 sec)

mysql select * from t3;

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

| id | fname | lname | birthday | c1 | c2 | c3 |

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

| 19 | lily19 | lucy19 | 2013-04-18 | 19 | 0 | 0 |

| 20 | lily20 | lucy20 | 2013-03-13 | 20 | 0 | 0 |

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

2 rows in set (0.00 sec)

mysql update t3 set birthday = '2022-02-23' where id = 19;

Query OK, 1 row affected (0.00 sec)

Rows matched: 1 Changed: 1 Warnings: 0

mysql select connection_id();

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

| connection_id() |

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

| 16 |

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

1 row in set (0.00 sec)

mysql

线程B, 我们用来进行普通的更新,但是遇到问题了,此时不知道是哪个线程把这行记录给锁定了?

mysql use test;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

mysql select @@autocommit;

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

| @@autocommit |

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

| 1 |

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

1 row in set (0.00 sec)

mysql update t3 set birthday='2018-01-03' where id = 19;

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

mysql select connection_id();

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

| connection_id() |

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

| 17 |

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

1 row in set (0.00 sec)

mysql show processlist;

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

| Id | User | Host | db | Command | Time | State | Info |

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

| 10 | root | localhost | NULL | Sleep | 1540 | | NULL |

| 11 | root | localhost | NULL | Sleep | 722 | | NULL |

| 16 | root | localhost | test | Sleep | 424 | | NULL |

| 17 | root | localhost | test | Query | 0 | init | show processlist |

| 18 | root | localhost | NULL | Sleep | 5 | | NULL |

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

5 rows in set (0.00 sec)

mysql show engine innodb status\G

------------

TRANSACTIONS

------------

Trx id counter 189327

Purge done for trx's n:o 189323 undo n:o 0 state: running but idle

History list length 343

LIST OF TRANSACTIONS FOR EACH SESSION:

---TRANSACTION 0, not started

MySQL thread id 11, OS thread handle 0x7f70a0c98700, query id 994 localhost root init

show engine innodb status

---TRANSACTION 189326, ACTIVE 2 sec starting index read

mysql tables in use 1, locked 1

LOCK WAIT 2 lock struct(s), heap size 376, 1 row lock(s)

MySQL thread id 17, OS thread handle 0x7f70a0bd5700, query id 993 localhost root updating

update t3 set birthday='2018-01-03' where id = 19

------- TRX HAS BEEN WAITING 2 SEC FOR THIS LOCK TO BE GRANTED:

RECORD LOCKS space id 529 page no 3 n bits 72 index `PRIMARY` of table `test`.`t3` trx id 189326 lock_mode X waiting

Record lock, heap no 2 PHYSICAL RECORD: n_fields 9; compact format; info bits 0

0: len 2; hex 3139; asc 19;;

1: len 6; hex 00000002e38c; asc ;;

2: len 7; hex 7e00000d2827c9; asc ~ (' ;;

3: len 6; hex 6c696c793139; asc lily19;;

4: len 6; hex 6c7563793139; asc lucy19;;

5: len 3; hex 8fcc57; asc W;;

6: len 4; hex 80000013; asc ;;

7: len 4; hex 80000000; asc ;;

8: len 4; hex 80000000; asc ;;

------------------

---TRANSACTION 189324, ACTIVE 641 sec

2 lock struct(s), heap size 376, 3 row lock(s), undo log entries 1

MySQL thread id 16, OS thread handle 0x7f70a0b94700, query id 985 localhost root cleaning up

Trx read view will not see trx with id = 189325, sees 189325

上面的信息很繁多,也看不清楚到底哪里是哪里。

不过现在,我们只要从数据字典里面拿出来这部分信息就OK了。

mysql SELECT * FROM information_schema.INNODB_TRX\G

*************************** 1. row ***************************

trx_id: 189324

trx_state: RUNNING

trx_started: 2013-04-18 17:48:14

trx_requested_lock_id: NULL

trx_wait_started: NULL

trx_weight: 3

trx_mysql_thread_id: 16

trx_query: NULL

trx_operation_state: NULL

trx_tables_in_use: 0

trx_tables_locked: 0

trx_lock_structs: 2

trx_lock_memory_bytes: 376

trx_rows_locked: 3

trx_rows_modified: 1

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 (0.01 sec)

mysql

原来是线程16忘掉COMMIT了。


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