pt-deadlock-logger使用

死锁监控pt-deadlock-logger

首先我们要创建一个表用来保存死锁的信息：

CREATE TABLE deadlocks (
server char() NOT NULL,
ts timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
thread int unsigned NOT NULL,
txn_id bigint unsigned NOT NULL,
txn_time smallint unsigned NOT NULL,
user char() NOT NULL,
hostname char() NOT NULL,
ip char() NOT NULL, -- alternatively, ip int unsigned NOT NULL
db char() NOT NULL,
tbl char() NOT NULL,
idx char() NOT NULL,
lock_type char() NOT NULL,
lock_mode char() NOT NULL,
wait_hold char() NOT NULL,
victim tinyint unsigned NOT NULL,
query text NOT NULL,
PRIMARY KEY (server,ts,thread)
) ENGINE=InnoDB；

然后开启死锁进程模拟死锁：

[root@mxqmongodb2 bin]# ./pt-deadlock-logger h=172.16.16.35,P=,u=root,p= --dest h=172.16.16.35,P=,D=test,t=deadlocks,u=root,p=
server ts thread txn_id txn_time user hostname ip db tbl idx lock_type lock_mode wait_hold victim query
172.16.16.35 --21T14::    root 172.16.16.35 test test idx RECORD X w  update test set id1= where id=
172.16.16.35 --21T14::    root 172.16.16.35 test test idx RECORD X w  update test set id1= where id=

在MySQL打开两个终端：

先看一下模拟表结构：

mysql> show create table test;
+-------+------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+------------------------------------------------------------------------------------------------------------------------------------------+
| test | CREATE TABLE `test` (
`id` int() DEFAULT NULL,
`id1` int() DEFAULT NULL,
KEY `idx` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+------------------------------------------------------------------------------------------------------------------------------------------+
 row in set (0.00 sec)
mysql> select * from test;
+------+------+
| id | id1 |
+------+------+
|  |  |
|  |  |
|  |  |
+------+------+
 rows in set (0.00 sec)

session1:

mysql> begin;
Query OK,  rows affected (0.00 sec)
mysql> select id1 from test where id= for update;
+------+
| id1 |
+------+
|  |
|  |
+------+
 rows in set (0.00 sec)
mysql> update test set id1= where id=;
Query OK,  row affected (0.00 sec)
Rows matched:  Changed:  Warnings:
mysql> commit

session2:

mysql> begin;
Query OK,  rows affected (0.00 sec)
mysql> select id1 from test where id= for update;
+------+
| id1 |
+------+
|  |
+------+
 row in set (0.00 sec)
mysql> update test set id1= where id=;
ERROR  (): Deadlock found when trying to get lock; try restarting transaction
mysql> commit

可见，MySQL提示已经出现了死锁，我们去看一下存储表：

mysql> select * from deadlocks\G
*************************** . row ***************************
server: 172.16.16.35
ts: -- ::
thread:
txn_id:
txn_time:
user: root
hostname:
ip: 172.16.16.35
db: test
tbl: test
idx: idx
lock_type: RECORD
lock_mode: X
wait_hold: w
victim:
query: update test set id1= where id=
*************************** . row ***************************
server: 172.16.16.35
ts: -- ::
thread:
txn_id:
txn_time:
user: root
hostname:
ip: 172.16.16.35
db: test
tbl: test
idx: idx
lock_type: RECORD
lock_mode: X
wait_hold: w
victim:
query: update test set id1= where id=
 rows in set (0.00 sec)

这会记录死锁的相关信息，但是这个对性能还是有一定影响的，一般情况就别开启了。