MySQL5.6锁阻塞分析
日常维护中，经常会碰到线程被阻塞，导致数据库响应非常慢，下面就看看如何获取是哪个线程导致了阻塞的。
blog地址：http://blog.csdn.net/hw_libo/article/details/39080809
1. 环境说明
RHEL 6.4 x86_64 + MySQL 5.6.19
事务隔离级别：RR
RHEL 6.4 x86_64 + MySQL 5.6.19
事务隔离级别：RR
2. 测试过程
3. 查看锁阻塞线程信息
这里用几中方法进行分析：
3.1 使用show processlist查看
MySQL [(none)]> show processlist;
+----+------+-----------+------+---------+------+--------------+------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+--------------+------------------------------------------+
| 2 | root | localhost | NULL | Query | 0 | init | show processlist |
| 3 | root | localhost | test | Query | 70 | Sending data | select count(*) from t3 a,t3 b |
| 4 | root | localhost | test | Query | 65 | updating | delete from emp where empno=7788 |
| 7 | root | localhost | test | Query | 68 | updating | update emp set sal=3500 where empno=7788 |
+----+------+-----------+------+---------+------+--------------+------------------------------------------+
4 rows in set (0.00 sec)
这里用几中方法进行分析：
3.1 使用show processlist查看
MySQL [(none)]> show processlist;
+----+------+-----------+------+---------+------+--------------+------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+--------------+------------------------------------------+
| 2 | root | localhost | NULL | Query | 0 | init | show processlist |
| 3 | root | localhost | test | Query | 70 | Sending data | select count(*) from t3 a,t3 b |
| 4 | root | localhost | test | Query | 65 | updating | delete from emp where empno=7788 |
| 7 | root | localhost | test | Query | 68 | updating | update emp set sal=3500 where empno=7788 |
+----+------+-----------+------+---------+------+--------------+------------------------------------------+
4 rows in set (0.00 sec)
如果数据库存在较多线程的话，这种方法确实不太好确认的。
3.2 直接使用show engine innodb status查看
------------
TRANSACTIONS
------------
Trx id counter 4131
Purge done for trx's n:o < 4119 undo n:o < 0 state: running but idle
History list length 126
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 2, OS thread handle 0x7f953ffff700, query id 115 localhost root init
show engine innodb status
---TRANSACTION 4130, ACTIVE 41 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 4, OS thread handle 0x7f953ff9d700, query id 112 localhost root updating
delete from emp where empno=7788
------- TRX HAS BEEN WAITING 41 SEC FOR THIS LOCK TO BE GRANTED: ## 等待了41s
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4130 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0 ## 线程4在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------------
---TRANSACTION 4129, ACTIVE 45 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 7, OS thread handle 0x7f953ff6c700, query id 111 localhost root updating
update emp set sal=3500 where empno=7788
------- TRX HAS BEEN WAITING 45 SEC FOR THIS LOCK TO BE GRANTED: ## 等待了45s
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4129 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0 ## 线程7在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------------
---TRANSACTION 4128, ACTIVE 51 sec
2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 3, OS thread handle 0x7f953ffce700, query id 110 localhost root cleaning up
------------
TRANSACTIONS
------------
Trx id counter 4131
Purge done for trx's n:o < 4119 undo n:o < 0 state: running but idle
History list length 126
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 2, OS thread handle 0x7f953ffff700, query id 115 localhost root init
show engine innodb status
---TRANSACTION 4130, ACTIVE 41 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 4, OS thread handle 0x7f953ff9d700, query id 112 localhost root updating
delete from emp where empno=7788
------- TRX HAS BEEN WAITING 41 SEC FOR THIS LOCK TO BE GRANTED: ## 等待了41s
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4130 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0 ## 线程4在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------------
---TRANSACTION 4129, ACTIVE 45 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 7, OS thread handle 0x7f953ff6c700, query id 111 localhost root updating
update emp set sal=3500 where empno=7788
------- TRX HAS BEEN WAITING 45 SEC FOR THIS LOCK TO BE GRANTED: ## 等待了45s
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4129 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0 ## 线程7在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------------
---TRANSACTION 4128, ACTIVE 51 sec
2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 3, OS thread handle 0x7f953ffce700, query id 110 localhost root cleaning up
我们知道，主要根因还是thread=3引起的，但从innodb status中却无法分析得到这个结果。
从上面来看，线程4和线程7都在等待往test.emp中的主键上加X锁，page num=3，但是线程7等待的时间为45s，而线程4等待的时间为41s，是较线程7之后申请的锁，所以可以判断是线程7阻塞了线程4。至于线程7为什么出现等待，这里分析不到根因。
从上面来看，线程4和线程7都在等待往test.emp中的主键上加X锁，page num=3，但是线程7等待的时间为45s，而线程4等待的时间为41s，是较线程7之后申请的锁，所以可以判断是线程7阻塞了线程4。至于线程7为什么出现等待，这里分析不到根因。
3.3 使用mysqladmin debug查看
# mysqladmin -S /tmp/mysql3306.sock debug
# mysqladmin -S /tmp/mysql3306.sock debug
然后在error日志中，会看到：
Thread database.table_name Locked/Waiting Lock_type
3 test.t3 Locked - read Low priority read lock
7 test.emp Locked - write High priority write lock
3 test.t3 Locked - read Low priority read lock
7 test.emp Locked - write High priority write lock
这种方法中，能找到线程ID=3和7是阻塞者，但还是不太准确，判断不出来线程7也是被线程ID=3阻塞的。
3.4 使用innodb_lock_monitor来获取阻塞锁线程
MySQL [test]> CREATE TABLE innodb_lock_monitor (a INT) ENGINE=INNODB; ## 随便在一个数据库中创建这个表，就会打开lock monitor
Query OK, 0 rows affected, 1 warning (0.07 sec)
MySQL [test]> show warnings\G
*************************** 1. row ***************************
Level: Warning
Code: 131
Message: Using the table name innodb_lock_monitor to enable diagnostic output is deprecated and may be removed in future releases. Use INFORMATION_SCHEMA or PERFORMANCE_SCHEMA tables or SET GLOBAL innodb_status_output=ON.
1 row in set (0.00 sec)
MySQL [test]> CREATE TABLE innodb_lock_monitor (a INT) ENGINE=INNODB; ## 随便在一个数据库中创建这个表，就会打开lock monitor
Query OK, 0 rows affected, 1 warning (0.07 sec)
MySQL [test]> show warnings\G
*************************** 1. row ***************************
Level: Warning
Code: 131
Message: Using the table name innodb_lock_monitor to enable diagnostic output is deprecated and may be removed in future releases. Use INFORMATION_SCHEMA or PERFORMANCE_SCHEMA tables or SET GLOBAL innodb_status_output=ON.
1 row in set (0.00 sec)
说明：这个在5.6中有一个warning，但不影响使用。
然后再使用show engine innodb status查看：
------------
TRANSACTIONS
------------
Trx id counter 4667
Purge done for trx's n:o < 4659 undo n:o < 0 state: running but idle
History list length 138
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 9, OS thread handle 0x7f813c5f7700, query id 152 localhost root init
show engine innodb status
---TRANSACTION 4663, ACTIVE 78 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 4, OS thread handle 0x7f813c628700, query id 149 localhost root updating
delete from emp where empno=7788
------- TRX HAS BEEN WAITING 78 SEC FOR THIS LOCK TO BE GRANTED: ## 等待了78s
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4663 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0 ## 线程4在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------------
TABLE LOCK table `test`.`emp` trx id 4663 lock mode IX ## 在给主键行上加X锁之前，先要在表上加意向锁IX
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4663 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
---TRANSACTION 4662, ACTIVE 81 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 7, OS thread handle 0x7f813c5c6700, query id 148 localhost root updating
update emp set sal=3500 where empno=7788
------- TRX HAS BEEN WAITING 81 SEC FOR THIS LOCK TO BE GRANTED: ## 等待了81s
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4662 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0 ## 线程7在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------------
TABLE LOCK table `test`.`emp` trx id 4662 lock mode IX ## 在给主键行上加X锁之前，先要在表上加意向锁IX
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4662 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
---TRANSACTION 4615, ACTIVE 1579 sec, thread declared inside InnoDB 1222
mysql tables in use 2, locked 0
2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 3, OS thread handle 0x7f813c659700, query id 147 localhost root Sending data
select count(*) from t3 a,t3 b ## 这是线程3当前正在执行的SQL
Trx read view will not see trx with id >= 4662, sees < 4659
TABLE LOCK table `test`.`emp` trx id 4615 lock mode IX ## 线程3中正在拥有表上的意向IX锁，并且有test.emp表上主键的行级X锁，page num=3
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4615 lock_mode X locks rec but not gap
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------
TRANSACTIONS
------------
Trx id counter 4667
Purge done for trx's n:o < 4659 undo n:o < 0 state: running but idle
History list length 138
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 9, OS thread handle 0x7f813c5f7700, query id 152 localhost root init
show engine innodb status
---TRANSACTION 4663, ACTIVE 78 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 4, OS thread handle 0x7f813c628700, query id 149 localhost root updating
delete from emp where empno=7788
------- TRX HAS BEEN WAITING 78 SEC FOR THIS LOCK TO BE GRANTED: ## 等待了78s
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4663 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0 ## 线程4在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------------
TABLE LOCK table `test`.`emp` trx id 4663 lock mode IX ## 在给主键行上加X锁之前，先要在表上加意向锁IX
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4663 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
---TRANSACTION 4662, ACTIVE 81 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 7, OS thread handle 0x7f813c5c6700, query id 148 localhost root updating
update emp set sal=3500 where empno=7788
------- TRX HAS BEEN WAITING 81 SEC FOR THIS LOCK TO BE GRANTED: ## 等待了81s
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4662 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0 ## 线程7在等待往test.emp中的主键上加X锁，page num=3
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
------------------
TABLE LOCK table `test`.`emp` trx id 4662 lock mode IX ## 在给主键行上加X锁之前，先要在表上加意向锁IX
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4662 lock_mode X locks rec but not gap waiting
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
---TRANSACTION 4615, ACTIVE 1579 sec, thread declared inside InnoDB 1222
mysql tables in use 2, locked 0
2 lock struct(s), heap size 360, 1 row lock(s)
MySQL thread id 3, OS thread handle 0x7f813c659700, query id 147 localhost root Sending data
select count(*) from t3 a,t3 b ## 这是线程3当前正在执行的SQL
Trx read view will not see trx with id >= 4662, sees < 4659
TABLE LOCK table `test`.`emp` trx id 4615 lock mode IX ## 线程3中正在拥有表上的意向IX锁，并且有test.emp表上主键的行级X锁，page num=3
RECORD LOCKS space id 16 page no 3 n bits 88 index `PRIMARY` of table `test`.`emp` trx id 4615 lock_mode X locks rec but not gap
Record lock, heap no 9 PHYSICAL RECORD: n_fields 10; compact format; info bits 0
0: len 4; hex 80001e6c; asc l;;
1: len 6; hex 000000001018; asc ;;
2: len 7; hex 91000001420084; asc B ;;
3: len 5; hex 53434f5454; asc SCOTT;;
4: len 7; hex 414e414c595354; asc ANALYST;;
5: len 4; hex 80001d8e; asc ;;
6: len 4; hex 208794f0; asc ;;
7: len 4; hex 80000bb8; asc ;;
8: SQL NULL;
9: len 4; hex 80000014; asc ;;
为什么线程3当前执行的是一个select t3表操作，但却锁住了test.emp表上page num=3？
有可能是线程3之前对test.emp表的操作事务没有及时提交导致。
所以得出：线程3阻塞了线程7，而线程7又阻塞了线程4，所以根因就是线程3，让线程3尽快提交或是kill掉即可。
有可能是线程3之前对test.emp表的操作事务没有及时提交导致。
所以得出：线程3阻塞了线程7，而线程7又阻塞了线程4，所以根因就是线程3，让线程3尽快提交或是kill掉即可。
4. 结论
在分析innodb中锁阻塞时，几种方法的对比情况：
在分析innodb中锁阻塞时，几种方法的对比情况：
（1）使用show processlist查看不靠谱；
（2）直接使用show engine innodb status查看，无法判断到问题的根因；
（3）使用mysqladmin debug查看，能看到所有产生锁的线程，但无法判断哪个才是根因；
（4）开启innodb_lock_monitor后，再使用show engine innodb status查看，能够找到锁阻塞的根因。
（2）直接使用show engine innodb status查看，无法判断到问题的根因；
（3）使用mysqladmin debug查看，能看到所有产生锁的线程，但无法判断哪个才是根因；
（4）开启innodb_lock_monitor后，再使用show engine innodb status查看，能够找到锁阻塞的根因。
blog地址：http://blog.csdn.net/hw_libo/article/details/39080809
---------------------
原文：https://blog.csdn.net/hw_libo/article/details/39080809
---------------------
原文：https://blog.csdn.net/hw_libo/article/details/39080809
MySQL 5.7中的方式是：
The specially named tables used to enable and disable the standard
InnoDB Monitor and InnoDB Lock Monitor (innodb_monitor and innodb_lock_monitor) are removed and replaced by two dynamic system variables: innodb_status_output and innodb_status_output_locks. For additional information, see Section 14.17, “InnoDB Monitors”.MySQL5.6锁阻塞分析的更多相关文章
- 通过Oracle补充日志，找到锁阻塞源头的SQL
问题背景: 有时会考虑一件事情,如果在Oracle环境下出现了锁阻塞的情况,如何定位到SQL源头(通过session.lock.transaction等视图仅能定位到会话)?或许有人会想有没有可能通过 ...
- SQL Server中CURD语句的锁流程分析
我只在数据库选项已开启“行版本控制的已提交读”(READ_COMMITTED_SNAPSHOT为ON)中进行了观察. 因此只适用于这种环境的数据库. 该类数据库支持四种不同事务隔离级别,下面分别观察数 ...
- linux RCU锁机制分析
openVswitch(OVS)源代码之linux RCU锁机制分析 分类: linux内核 | 标签: 云计算,openVswitch,linux内核,RCU锁机制 | 作者: yuzhih ...
- Redisson 实现分布式锁原理分析
Redisson 实现分布式锁原理分析 写在前面 在了解分布式锁具体实现方案之前,我们应该先思考一下使用分布式锁必须要考虑的一些问题. 互斥性:在任意时刻,只能有一个进程持有锁. 防死锁:即使有 ...
- SQL Server 阻塞分析
一.加锁(locking).阻塞(blocking).死锁(deadlock)定义 加锁:用于管理多个连接的进程.当连接需要访问一块数据时,在这些数据上放置某种类型的锁. 阻塞 ...
- MySQL锁等待分析【2】
MySQL锁等待分析[1]中对锁等待的分析是一步一步来的.虽然最后是分析出来了,可是用时是比较长的:理清各个表之间的关系后,得到如下SQL语句,方便以后使用 select block_trx.trx_ ...
- 再谈DOMContentLoaded与渲染阻塞—分析html页面事件与资源加载
浏览器的多线程中,有的线程负责加载资源,有的线程负责执行脚本,有的线程负责渲染界面,有的线程负责轮询.监听用户事件. 这些线程,根据浏览器自身特点以及web标准等等,有的会被浏览器特意的阻塞.两个很明 ...
- DB2 锁问题分析与解释
DB2 锁问题分析与解释 DB2 应用中常常会遇到锁超时与死锁现象,那么这样的现象产生的原因是什么呢.本文以试验的形式模拟锁等待.锁超时.死锁现象.并给出这些现象的根本原因. 试验环境: DB2 v9 ...
- Java多线程——线程八锁案例分析
Java多线程——线程八锁案例分析 摘要:本文主要学习了多线程并发中的一些案例. 部分内容来自以下博客: https://blog.csdn.net/dyt443733328/article/deta ...
随机推荐
- XAML属性赋值转换之谜（WPF XAML语法解密）
XAML与XML类似,就是XML延伸过来的.为了更好的表达一些功能,WPF对XML做了扩展,有些功能是WPF在后台悄悄的替你做了.有时候,虽然实现了某个功能,但是对实现原理还是很茫然.今天就讲讲XAM ...
- 如何查找SHELL的进程号并杀死
一.shell查找进程并杀死 #!/bin/sh tomcat_id=`ps -ef | grep tomcat | grep -v "grep" | awk '{print $2 ...
- Java中的简单工厂模式（转）
Java中的简单工厂模式 举两个例子以快速明白Java中的简单工厂模式: 女娲抟土造人话说:“天地开辟,未有人民,女娲抟土为人.”女娲需要用土造出一个个的人,但在女娲造出人之前,人的概念只存在于女娲的 ...
- 27-hadoop-hbase安装
hbase的安装分为单机模式和完全分布式 单机模式 单机模式的安装很简单, 需要注意hbase自己内置一个zookeeper, 如果使用单机模式, 那么该机器的zookeepr不可以启动 1, 添加j ...
- 基于GoogLeNet的不同花分类微调训练案例
import tensorflow as tf from tensorflow.contrib.slim import nets slim = tf.contrib.slim import numpy ...
- SQL Server T—SQL 视图 事务
一 视图 视图是存储在数据库中的查询的SQL 语句, 视图是从一个或多个表或视图中导出的表,是一张虚表,只能对视图进行查询,不能增.删.改. 对视图进行修改要在相应的基本表中进行修改,修改会自动的反应 ...
- Romantic（hdu2699+欧几里德）
Romantic Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Subm ...
- Charlie's Change（完全背包+路径记忆）
Charlie's Change Time Limit: 1000MS Memory Limit: 30000K Total Submissions: 3176 Accepted: 913 D ...
- springboot学习-springboot使用spring-data-jpa操作MySQL数据库
我们在上一篇搭建了一个简单的springboot应用,这一篇将介绍使用spring-data-jpa操作数据库. 新建一个MySQL数据库,这里数据库名为springboot,建立user_info数 ...
- JAVA设计模式详解（五）----------适配器模式
各位朋友好,本章节我们继续讲第五个设计模式. 在生活中,我们都知道手机内存卡是无法直接接电脑的,因为内存卡的卡槽比较小,而电脑只有USB插孔,此时我们需要用到读卡器.这个读卡器就相当于是适配器.这是生 ...