接上一篇，未提交的事务导致锁等待，锁住一段时间后又提交了（也可能是回滚），锁释放业务继续运行。那么我们如何知道产生锁的事务是在跑什么SQL？
今天讲的这个工具，就可以通过监听3306端口的数据，把每个事务的起始时间，SQL命令都打印出来，而且可以设置事务时长，比如事务时长超过10秒的。
参考链接：https://highdb.com/%E8%BF%BD%E8%B8%AAmysql%E4%B8%AD%E9%95%BF%E6%97%B6%E9%97%B4%E8%BF%90%E8%A1%8C%E7%9A%84%E4%BA%8B%E5%8A%A1/
github链接：https://github.com/yoshinorim/MySlowTranCapture,下载后解压
#安装
How to use: * Install libpcap, libpcap-devel, boost, and boost-devel if not installed * make * make install * Run myslowtrancapture
#运行
[root@xxxx MySlowTranCapture-master]# myslowtrancapture -f "tcp port 3306" Monitoring any interface.. Filtering rule: tcp port 3306 Logging transactions that take more than 4000 milliseconds.. ........开始等待符合条件的输出
#默认检测事务时长是4秒，我们构造一个显式事务，持续时间5秒，看看输出结果
#MYSQL SESSION mysql> select * from t1; +------+ | id | +------+ | 3 | | 4 | +------+ 2 rows in set (0.00 sec) mysql> begin;delete from t1 where id=3;select sleep(5);rollback; Query OK, 0 rows affected (0.00 sec) Query OK, 1 row affected (0.00 sec) +----------+ | sleep(5) | +----------+ | 0 | +----------+ 1 row in set (5.00 sec) Query OK, 0 rows affected (0.00 sec) mysql>
From 10.3.171.21:55871 2017/02/27 11:25:18.679918 -> begin #事务开始 2017/02/27 11:25:18.679992 <- GOT_OK 2017/02/27 11:25:18.679995 <- GOT_OK 2017/02/27 11:25:18.680104 -> delete from t1 where id=3 #这里看到了事务SQL 2017/02/27 11:25:18.680336 <- GOT_OK 2017/02/27 11:25:18.680342 <- GOT_OK 2017/02/27 11:25:18.680477 -> select sleep(5) 2017/02/27 11:25:23.680669 <- GOT_RES 2017/02/27 11:25:23.680677 <- GOT_RES 2017/02/27 11:25:23.680973 -> rollback #事务回滚
#事务时长=11:25:23-11:25:18=5秒
除了rollback,commit之外，给当前session设置autocommit=0/1,也会提交当前事务-------这句话有问题，单独开事务测试并没有提交，在这里看日志又像是事务终止了，需要再调查下。
From 10.3.171.21:46378 2017/02/27 12:33:37.484762 -> begin 2017/02/27 12:33:37.484806 <- GOT_OK 2017/02/27 12:33:37.484808 <- GOT_OK 2017/02/27 12:33:37.484958 -> delete from test 2017/02/27 12:33:37.485061 <- GOT_OK 2017/02/27 12:33:37.485063 <- GOT_OK 2017/02/27 12:33:37.485167 -> select sleep(200) 2017/02/27 12:36:57.485276 <- GOT_RES 2017/02/27 12:36:57.485279 <- GOT_RES 2017/02/27 12:36:57.485442 -> TRAN_END BY set autocommit=0 #set autocommit=0 From 10.3.139.151:6610
产生上面输出的SQL是这样的：
mysql> begin;delete from test;select sleep(200);set autocommit=0; Query OK, 0 rows affected (0.00 sec) Query OK, 5 rows affected (0.00 sec) +------------+ | sleep(200) | +------------+ | 0 | +------------+ 1 row in set (3 min 19.98 sec) Query OK, 0 rows affected (0.00 sec) mysql>