上图是在 Sysbench 所在ECS 上抓包可以看到所有连接都是这样，注意第四个包是 Server端在3次握手成功后发了 Server Greeting 给客户端 Sysbench，此时Sysbench 应该发自己的账号密码来 Login但是抓包永远卡在这里，也就是Sysbench 建立完连接后跑了，不搭理服务端发了什么，这也是为什么最前面的 netstat -anto 看到 Recv-Q 这列总是79，这79长度的内容就是 Server 发给Sysbench 的 Server Greeting 内容，本该Sysbench 去读走 Server Greeting 然后按照MySQL 协议发账号密码，但是不，此时Sysbench 颠了，不管这个连接了，又去创建新连接于是重复上面的过程；直到本地端口用完，sys CPU 干到 100%
其实上面这个抓包的连接状态是 ESTABLISHED 状态，为什么最终看到的是 CLOSE_WAIT 呢，因为 Server发了 Server Greeting 后有一个超时时间，迟迟等不到Sysbench Client的账号密码就会发 FIN 给Client 端请求断开这个连接，导致Client断的连接状态从 ESTABLISHED 进入 CLOSE_WAIT ，这从上面的 TCP 状态图完全可以推导出来，扩大抓包时间的话会抓到 Server 发过来的 FIN 包
# netstat -anto | head -30 |grep -E "State|:3306 " Proto Recv-Q Send-Q Local Address Foreign Address State Timer tcp 78 0 192.168.0.1:46344 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:44592 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:45908 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:44166 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:59484 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:60720 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:53436 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:58690 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:35932 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:53944 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:59758 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:53676 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:59304 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:41848 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:44312 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:56654 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:3516 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:39316 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:55074 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:59476 192.168.20.220:3306 ESTABLISHED off (0.00/0/0) tcp 78 0 192.168.0.1:48854 192.168.20.220:3306 ESTABLISHED off (0.00/0/0)
#pstack 1448113 Thread 3 (Thread 0x7f9a0b23c640 (LWP 1448115)): #0 0x00007f9a0b9722bb in connect () from /lib64/libpthread.so.0 #1 0x00007f9a0bb02b00 in pvio_socket_internal_connect (pvio=0x7f99fa5db270, name=0x7f99fc0247c0, namelen=16) at /root/mariadb-connector-c-3.2.6/plugins/pvio/pvio_socket.c:642 #2 0x00007f9a0bb02d76 in pvio_socket_connect_sync_or_async (pvio=0x7f99fa5db270, name=0x7f99fc0247c0, namelen=16) at /root/mariadb-connector-c-3.2.6/plugins/pvio/pvio_socket.c:750 #3 0x00007f9a0bb03499 in pvio_socket_connect (pvio=0x7f99fa5db270, cinfo=0x7f9a0b23b3d0) at /root/mariadb-connector-c-3.2.6/plugins/pvio/pvio_socket.c:919 #4 0x00007f9a0bb15277 in ma_pvio_connect (pvio=0x7f99fa5db270, cinfo=0x7f9a0b23b3d0) at /root/mariadb-connector-c-3.2.6/libmariadb/ma_pvio.c:484 #5 0x00007f9a0bb0b59c in mthd_my_real_connect (mysql=0x7f99fc01ff50, host=0x14e4110 "127.0.0.1", user=0x14e27c0 "root", passwd=0x14e40c0 "123", db=0x14e28f0 "test", port=3306, unix_socket=0x0, client_flag=65536) at /root/mariadb-connector-c-3.2.6/libmariadb/mariadb_lib.c:1462 #6 0x00007f9a0bb0affb in mysql_real_connect (mysql=0x7f99fc01ff50, host=0x14e4110 "127.0.0.1", user=0x14e27c0 "root", passwd=0x14e40c0 "123", db=0x14e28f0 "test", port=3306, unix_socket=0x0, client_flag=65536) at /root/mariadb-connector-c-3.2.6/libmariadb/mariadb_lib.c:1301 #7 0x000000000041b5d0 in mysql_drv_real_connect (db_mysql_con=0x7f99fc01fbf0) at drv_mysql.c:405 #8 0x000000000041cc6c in mysql_drv_reconnect (sb_con=0x0) at drv_mysql.c:815 #9 check_error (sb_con=sb_con@entry=0x7f99fc0210a0, func=func@entry=0x486637 "mysql_drv_query()", query=query@entry=0x7f99fc0207f0 "SELECT c FROM sbtest16 WHERE id=5031", counter=counter@entry=0x7f99fc0210c8) at drv_mysql.c:894 #10 0x000000000041d1d1 in mysql_drv_query (rs=0x7f99fc0210c8, len=<optimized out>, query=0x7f99fc0207f0 "SELECT c FROM sbtest16 WHERE id=5031", sb_conn=<optimized out>) at drv_mysql.c:1071 #11 mysql_drv_query (rs=0x7f99fc0210c8, len=<optimized out>, query=0x7f99fc0207f0 "SELECT c FROM sbtest16 WHERE id=5031", sb_conn=<optimized out>) at drv_mysql.c:1051 #12 mysql_drv_execute (stmt=<optimized out>, rs=<optimized out>) at drv_mysql.c:1040 #13 0x000000000040f32a in db_execute (stmt=0x7f99fc021270) at db_driver.c:517
[root@plantegg 11:25 /root] #mysql -h127.0.0.1 --ssl-mode=DISABLED -uroot -p123 test mysql: [Warning] Using a password on the command line interface can be insecure.
#mysql -h127.0.0.1 --ssl-mode=DISABLED -uroot -p123 test mysql: [Warning] Using a password on the command line interface can be insecure. ERROR 1040 (HY000): Too many connections
用完端口后： getpid() = 1515928 socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) = 3 connect(3, {sa_family=AF_INET, sin_port=htons(3306), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EADDRNOTAVAIL (Cannot assign requested address) shutdown(3, SHUT_RDWR) = -1 ENOTCONN (Transport endpoint is not connected) close(3) = 0 fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(0x88, 0), ...}) = 0 write(2, "ERROR 2003 (HY000): ", 20ERROR 2003 (HY000): ) = 20 write(2, "Can't connect to MySQL server on"..., 54Can't connect to MySQL server on '127.0.0.1:3306' (99)) = 54 write(2, "\n", 1 ) = 1 write(1, "\7", 1) = 1 #mysql -h127.0.0.1 --ssl-mode=DISABLED -uroot -p123 test mysql: [Warning] Using a password on the command line interface can be insecure. ERROR 2003 (HY000): Can't connect to MySQL server on '127.0.0.1:3306' (99)
[root@plantegg 11:54 /root] #mysql --show-warnings=FALSE -h127.0.0.1 --ssl-mode=DISABLED -uroot -p123 test mysql: [Warning] Using a password on the command line interface can be insecure. ERROR 2003 (HY000): Can't connect to MySQL server on '127.0.0.1:3306' (111)
账号密码权限错误
1 2
#mysql --show-warnings=FALSE -h127.0.0.1 --ssl-mode=DISABLED -uroot -p1234 test ERROR 1045 (28000): Access denied for user 'root'@'127.0.0.1' (using password: YES)
//正常telnet ，能看到 Greeting以及输密码信息 #telnet 127.0.0.1 3306 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. I 8.2.0�#[6Y @+5=,mi?%#caching_sha2_password^]
//当MySQL-Server 的连接数不够了时 #telnet 127.0.0.1 3306 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. Too many connectionsConnection closed by foreign host.
上图是在 Sysbench 所在ECS 上抓包可以看到所有连接都是这样，注意第四个包是 Server端在3次握手成功后发了 Server Greeting 给客户端 Sysbench，此时Sysbench 应该发自己的账号密码来 Login但是抓包永远卡在这里，也就是Sysbench 建立完连接后跑了，不搭理服务端发了什么，这也是为什么最前面的 netstat -anto 看到 Recv-Q 这列总是79，这79长度的内容就是 Server 发给Sysbench 的 Server Greeting 内容，本该Sysbench 去读走 Server Greeting 然后按照MySQL 协议发账号密码，但是不，此时Sysbench 颠了，不管这个连接了，又去创建新连接于是重复上面的过程；直到本地端口用完，sys CPU 干到 100%
