1、查詢進程
show processlist
2、 查詢到相對應的進程,然后 kill id
驗證(kill后再看是否還有鎖)
2、查詢是否鎖表
show OPEN TABLES where In_use > 0;
示例:
新建一個會話執行如下的顯示鎖示例
LOCK TABLES account_data.account READ; SELECT SLEEP(160); UNLOCK TABLES account_data.account;
另開啟一個會話檢查鎖表情況:
mysql> show OPEN TABLES where In_use > 0; +--------------+---------+--------+-------------+ | Database | Table | In_use | Name_locked | +--------------+---------+--------+-------------+ | account_data | account | 1 | 0 | +--------------+---------+--------+-------------+ 1 row in set (0.00 sec)mysql> select * from information_schema.innodb_locks\G;
Empty set, 1 warning (0.00 sec)ERROR:
No query specifiedmysql> show processlist\G;
1. row
Id: 5
User: root
Host: 192.168.0.206:64294
db: NULL
Command: Sleep
Time: 4051
State:
Info: NULL
2. row
Id: 8
User: root
Host: 192.168.0.206:64297
db: NULL
Command: Sleep
Time: 4042
State:
Info: NULL
3. row
Id: 10
User: root
Host: localhost
db: NULL
Command: Query
Time: 0
State: starting
Info: show processlist
4. row
Id: 19
User: root
Host: 192.168.0.206:54603
db: account_data
Command: Sleep
Time: 245
State:
Info: NULL
5. row
Id: 20
User: root
Host: 192.168.0.206:54604
db: information_schema
Command: Query
Time: 20
State: User sleep
Info: select sleep(160)
5 rows in set (0.00 sec)ERROR:
No query specifiedmysql>
3、在5.5中,information_schema 庫中增加了三個關於鎖的表(innoDB引擎):
innodb_trx ## 當前運行的所有事務
innodb_locks ## 當前出現的鎖
innodb_lock_waits ## 鎖等待的對應關系
先來看一下這三張表結構:
root@127.0.0.1 : information_schema 13:28:38> desc innodb_locks; +————-+———————+——+—–+———+——-+ | Field | Type | Null | Key | Default | Extra | +————-+———————+——+—–+———+——-+ | lock_id | varchar(81) | NO | | | |#鎖ID | lock_trx_id | varchar(18) | NO | | | |#擁有鎖的事務ID | lock_mode | varchar(32) | NO | | | |#鎖模式 | lock_type | varchar(32) | NO | | | |#鎖類型 | lock_table | varchar(1024) | NO | | | |#被鎖的表 | lock_index | varchar(1024) | YES | | NULL | |#被鎖的索引 | lock_space | bigint(21) unsigned | YES | | NULL | |#被鎖的表空間號 | lock_page | bigint(21) unsigned | YES | | NULL | |#被鎖的頁號 | lock_rec | bigint(21) unsigned | YES | | NULL | |#被鎖的記錄號 | lock_data | varchar(8192) | YES | | NULL | |#被鎖的數據 +————-+———————+——+—–+———+——-+ 10 rows in set (0.00 sec)root@127.0.0.1 : information_schema 13:28:56> desc innodb_lock_waits;
+——————-+————-+——+—–+———+——-+
| Field | Type | Null | Key | Default | Extra |
+——————-+————-+——+—–+———+——-+
| requesting_trx_id | varchar(18) | NO | | | |#請求鎖的事務ID
| requested_lock_id | varchar(81) | NO | | | |#請求鎖的鎖ID
| blocking_trx_id | varchar(18) | NO | | | |#當前擁有鎖的事務ID
| blocking_lock_id | varchar(81) | NO | | | |#當前擁有鎖的鎖ID
+——————-+————-+——+—–+———+——-+
4 rows in set (0.00 sec)root@127.0.0.1 : information_schema 13:29:05> desc innodb_trx ;
+—————————-+———————+——+—–+———————+——-+
| Field | Type | Null | Key | Default | Extra |
+—————————-+———————+——+—–+———————+——-+
| trx_id | varchar(18) | NO | | | |#事務ID
| trx_state | varchar(13) | NO | | | |#事務狀態:
| trx_started | datetime | NO | | 0000-00-00 00:00:00 | |#事務開始時間;
| trx_requested_lock_id | varchar(81) | YES | | NULL | |#innodb_locks.lock_id
| trx_wait_started | datetime | YES | | NULL | |#事務開始等待的時間
| trx_weight | bigint(21) unsigned | NO | | 0 | |#
| trx_mysql_thread_id | bigint(21) unsigned | NO | | 0 | |#事務線程ID
| trx_query | varchar(1024) | YES | | NULL | |#具體SQL語句
| trx_operation_state | varchar(64) | YES | | NULL | |#事務當前操作狀態
| trx_tables_in_use | bigint(21) unsigned | NO | | 0 | |#事務中有多少個表被使用
| trx_tables_locked | bigint(21) unsigned | NO | | 0 | |#事務擁有多少個鎖
| trx_lock_structs | bigint(21) unsigned | NO | | 0 | |#
| trx_lock_memory_bytes | bigint(21) unsigned | NO | | 0 | |#事務鎖住的內存大小(B)
| trx_rows_locked | bigint(21) unsigned | NO | | 0 | |#事務鎖住的行數
| trx_rows_modified | bigint(21) unsigned | NO | | 0 | |#事務更改的行數
| trx_concurrency_tickets | bigint(21) unsigned | NO | | 0 | |#事務並發票數
| trx_isolation_level | varchar(16) | NO | | | |#事務隔離級別
| trx_unique_checks | int(1) | NO | | 0 | |#是否唯一性檢查
| trx_foreign_key_checks | int(1) | NO | | 0 | |#是否外鍵檢查
| trx_last_foreign_key_error | varchar(256) | YES | | NULL | |#最后的外鍵錯誤
| trx_adaptive_hash_latched | int(1) | NO | | 0 | |#
| trx_adaptive_hash_timeout | bigint(21) unsigned | NO | | 0 | |#
+—————————-+———————+——+—–+———————+——-+
22 rows in set (0.01 sec)
查看正在鎖的事務
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCKS;
查看等待鎖的事務
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCK_WAITS;
查看鎖阻塞線程信息
3.1 使用show processlist查看
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 ## 線程4在等待往test.emp中的主鍵上加X鎖,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 indexPRIMARY
of tabletest
.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 ## 線程7在等待往test.emp中的主鍵上加X鎖,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
我們知道,主要根因還是thread=3引起的,但從innodb status中卻無法分析得到這個結果。
從上面來看,線程4和線程7都在等待往test.emp中的主鍵上加X鎖,page num=3,但是線程7等待的時間為45s,而線程4等待的時間為41s,是較線程7之后申請的鎖,所以可以判斷是線程7阻塞了線程4。至於線程7為什么出現等待,這里分析不到根因。
3.3 使用mysqladmin debug查看
# mysqladmin -S /tmp/mysql3306.sock debug
然后在error日志中,會看到:
Thread database.table_name Locked/Waiting Lock_type3 test.t3 Locked - read Low priority read lock
7 test.emp Locked - write High priority write lock
這種方法中,能找到線程ID=3和7是阻塞者,但還是不太准確,判斷不出來線程7也是被線程ID=3阻塞的。
3.4 使用innodb_lock_monitor來獲取阻塞鎖線程
MySQL [test]> CREATE TABLE innodb_lock_monitor (a INT) ENGINE=INNODB; ## 隨便在一個數據庫中創建這個表,就會打開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)
說明:這個在5.6中有一個warning,但不影響使用。
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 ## 線程4在等待往test.emp中的主鍵上加X鎖,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 ## 在給主鍵行上加X鎖之前,先要在表上加意向鎖IX
RECORD LOCKS space id 16 page no 3 n bits 88 indexPRIMARY
of tabletest
.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 indexPRIMARY
of tabletest
.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 ## 線程7在等待往test.emp中的主鍵上加X鎖,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 ## 在給主鍵行上加X鎖之前,先要在表上加意向鎖IX
RECORD LOCKS space id 16 page no 3 n bits 88 indexPRIMARY
of tabletest
.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 ## 這是線程3當前正在執行的SQL
Trx read view will not see trx with id >= 4662, sees < 4659
TABLE LOCK tabletest
.emp
trx id 4615 lock mode IX ## 線程3中正在擁有表上的意向IX鎖,並且有test.emp表上主鍵的行級X鎖,page num=3
RECORD LOCKS space id 16 page no 3 n bits 88 indexPRIMARY
of tabletest
.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 ;;
為什么線程3當前執行的是一個select t3表操作,但卻鎖住了test.emp表上page num=3?
有可能是線程3之前對test.emp表的操作事務沒有及時提交導致。
所以得出:線程3阻塞了線程7,而線程7又阻塞了線程4,所以根因就是線程3,讓線程3盡快提交或是kill掉即可。
3.5、 查看表鎖的情況:
mysql> show status like 'table%'; +----------------------------+---------+ | Variable_name | Value | +----------------------------+---------+ | Table_locks_immediate | 100 | | Table_locks_waited | 11 | +----------------------------+---------+
3.6、查看InnoDB_row_lock狀態變量來分析系統上的行鎖的爭奪情況:
mysql> show status like 'InnoDB_row_lock%'; +-------------------------------+--------+ | Variable_name | Value | +-------------------------------+--------+ | Innodb_row_lock_current_waits | 0 | | Innodb_row_lock_time | 159372 | | Innodb_row_lock_time_avg | 39843 | | Innodb_row_lock_time_max | 51154 | | Innodb_row_lock_waits | 4 | +-------------------------------+--------+ 5 rows in set (0.01 sec)mysql>
4. 結論
在分析innodb中鎖阻塞時,幾種方法的對比情況:
(1)使用show processlist查看不靠譜;
(2)直接使用show engine innodb status查看,無法判斷到問題的根因;
(3)使用mysqladmin debug查看,能看到所有產生鎖的線程,但無法判斷哪個才是根因;
(4)開啟innodb_lock_monitor后,再使用show engine innodb status查看,能夠找到鎖阻塞的根因。
參考:http://blog.csdn.net/hw_libo/article/details/39080809
原文地址:https://www.cnblogs.com/duanxz/p/4394641.html