如何查看MySQL数据库一段时间内的连接情况？两种方式来解锁~

后台有DBA小伙伴问到一个问题：如何查看 MySQL 数据库一段时间内的连接情况呢？

据小编了解，查看方式已知至少有两种方式可以实现，让我们一起往下解锁吧~

方式一：开启 general_log 就可以观察到

• 开启命令

mysql> set global general_log=ON;

• 执行一些操作

[root@mgr2 ~]# mysql -uGreatSQL -pGreatSQL -h192.168.6.217 -P3306
mysql> use test;
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| book           |
| student        |
| t1             |
+----------------+
3 rows in set (0.01 sec)

mysql> select * from t1;
+------+--------+
| id   | name   |
+------+--------+
|    1 | 哈哈   |
|    2 | 你好   |
|    3 | 呵呵   |
+------+--------+
5 rows in set (0.00 sec)

mysql> delete from test.t1 where id=4;
Query OK, 1 row affected (0.02 sec)

• 查看general_log日志信息，已经完整记录到了。

2022-01-20T21:46:17.073491-05:00           32 Connect   GreatSQL@192.168.6.216 on  using TCP/IP
2022-01-20T21:46:17.074048-05:00           32 Query     select @@version_comment limit 1
2022-01-20T21:46:20.217080-05:00           32 Query     SELECT DATABASE()
2022-01-20T21:46:20.217657-05:00           32 Init DB   test
2022-01-20T21:46:20.218960-05:00           32 Query     show databases
2022-01-20T21:46:20.220347-05:00           32 Query     show tables
2022-01-20T21:46:20.222050-05:00           32 Field List        book
2022-01-20T21:46:20.222644-05:00           32 Field List        student
2022-01-20T21:46:20.223106-05:00           32 Field List        t1
2022-01-20T21:46:22.856100-05:00           32 Query     show tables
2022-01-20T21:46:31.156616-05:00           32 Query     select * from t1
2022-01-20T21:46:43.136448-05:00           32 Query     delete from test.t1 where id=4

方式二：抓包

• 这里采用 MySQL Sniffer 进行抓包。

1.MySQL Sniffer 介绍

• MySQL Sniffer ：是一个基于 MySQL 协议的抓包工具，实时抓取 MySQL Server 端的请求，并格式化输出。
• 输出内容：包括访问时间、访问用户、来源 IP、访问Database、命令耗时、返回数据行数、执行语句等。有批量抓取多个端口，后台运行，日志分割等多种使用方式，操作便捷，输出友好。
• 开源出品：奇虎360 github
• github地址：https://github.com/Qihoo360/mysql-sniffer/blob/master/README_CN.md

2.安装依赖包

yum install gcc gcc-c++ cmake libpcap-devel glib2-devel libnet-devel -y

3.安装命令

git clone https://github.com/Qihoo360/mysql-sniffer.git
cd mysql-sniffer
mkdir proj
cd proj
cmake ../
make

编译过程中出现一些问题，参考 https://www.cnblogs.com/kerrycode/p/14948381.html 解决，感谢！

4.查看帮助

• 安装后工具在 bin 目录下。

[root@mgr3 bin]# ./mysql-sniffer -help
Usage ./mysql-sniffer [-d] -i eth0 -p 3306,3307,3308 -l /var/log/mysql-sniffer/ -e stderr
         [-d] -i eth0 -r 3000-4000
         -d daemon mode.
         -s how often to split the log file(minute, eg. 1440). if less than 0, split log everyday
         -i interface. Default to eth0
         -p port, default to 3306. Multiple ports should be splited by ','. eg. 3306,3307
            this option has no effect when -f is set.
         -r port range, Don't use -r and -p at the same time
         -l query log DIRECTORY. Make sure that the directory is accessible. Default to stdout.
         -e error log FILENAME or 'stderr'. if set to /dev/null, runtime error will not be recorded
         -f filename. use pcap file instead capturing the network interface
         -w white list. dont capture the port. Multiple ports should be splited by ','.
         -t truncation length. truncate long query if it's longer than specified length. Less than 0 means no truncation
         -n keeping tcp stream count, if not set, default is 65536. if active tcp count is larger than the specified count, mysql-sniffer will remove the oldest one

5.测试

a.实时抓取某端口信息并打印到屏幕

输出格式为：时间，访问用户，来源 IP，访问 Database，命令耗时，返回数据行数，执行语句。

• 控制台监听

• 执行一些操作

mysql> use test;
Database changed
mysql> create table t1 (id int(11) not null auto_increment, name varchar(64), primary key(id));
Query OK, 0 rows affected (0.06 sec)

mysql> insert into t1 values (1,'小明'),(2,'小陈');
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> delete from t1 where id=1;
Query OK, 1 row affected (0.00 sec)

mysql> select * from t1;
+----+--------+
| id | name   |
+----+--------+
|  2 | 小陈   |
+----+--------+
1 row in set (0.00 sec)

• 控制台输出

2022-01-21 14:37:09      GreatSQL        192.168.6.216   NULL             0ms             1      select @@version_comment limit 1
2022-01-21 14:37:31      GreatSQL        192.168.6.216   NULL             0ms             2      show databases
2022-01-21 14:37:37      GreatSQL        192.168.6.216   NULL             0ms             1      SELECT DATABASE()
2022-01-21 14:37:37      GreatSQL        192.168.6.216   test             0ms             0      use test
2022-01-21 14:37:37      GreatSQL        192.168.6.216   test             0ms             2      show databases
2022-01-21 14:37:37      GreatSQL        192.168.6.216   test            11ms             0      show tables
2022-01-21 14:41:58      GreatSQL        192.168.6.216   test            60ms             0      create table t1 (id int(11) not null auto_increment, name varchar(64), primary key(id))
2022-01-21 14:42:40      GreatSQL        192.168.6.216   test             0ms             2      insert into t1 values (1,'小明'),(2,'小陈')
2022-01-21 14:42:54      GreatSQL        192.168.6.216   test             0ms             1      delete from t1 where id=1
2022-01-21 14:43:04      GreatSQL        192.168.6.216   test             0ms             1      select * from t1

• 目前看有正常抓取到信息

b、可以把抓包的数据存储到文件

• 文件名称就是端口号，如果文件没内容，可以改成MySQL用户权限组试一下

./mysql-sniffer -i eth1 -p 33061 -l ./

[root@mgr3 bin]# more 33061.log
2022-01-21 15:00:11      NULL    192.168.6.216   test             0ms             0      use test
2022-01-21 15:00:11      NULL    192.168.6.216   test             0ms             1      SELECT DATABASE()

• 其他功能就不一一测试了

• 特别注意，以上是在 MySQL5.6 版本测试获取的，在 8.0版本中可能由于MySQL协议变更导致抓不到数据包，同时该工具存在一定的丢包情况。

Enjoy GreatSQL 😃