After a TCP connection has been closed, the state changes to TIME_WAIT. If I recall correctly, this is a way to prevent the same port from being immediately reused, and allow any duplicate packets from the previous connection that might still be floating around the network time to expire. In general, the presence of TIME_WAIT isn't something to be too concerned about.
If you see a large number of these, it may be because your application is opening a new database connection for each web server request. You might be able to save yourself a bit of overhead by refactoring your application to use a database connection pool. -Travis -----Original Message----- From: Madan Thapa [mailto:madan.feedb...@gmail.com] Sent: Wednesday, February 16, 2011 3:35 PM To: mysql@lists.mysql.com Subject: mysql TIME_WAIT Hi, When i do a netstat and grep port 3306 , i can see lots of TIME_WAIT. Can you please advise , what might be the issue for so many TIME_WAIT ? Here are the logs and related files: My.CNF on DB Server ############################## ## [root@sql mysql]# cat /etc/my.cnf [mysqld] safe-show-database skip-locking skip-bdb port = 3306 socket = /var/lib/mysql/mysql.sock skip-locking key_buffer = 384M max_allowed_packet = 16M table_cache = 512 sort_buffer_size = 2M read_buffer_size = 2M read_rnd_buffer_size = 8M myisam_sort_buffer_size = 64M thread_cache_size = 8 query_cache_size = 32M # Try number of CPU's*2 for thread_concurrency thread_concurrency = 4 max_connections=5000 long_query_time = 20 log-slow-queries=/var/log/mysqld-slow.log [mysqldump] quick max_allowed_packet = 16M [mysql] no-auto-rehash # Remove the next comment character if you are not familiar with SQL safe-updates [isamchk] key_buffer = 256M sort_buffer_size = 256M read_buffer = 2M write_buffer = 2M [myisamchk] key_buffer = 256M sort_buffer_size = 256M read_buffer = 2M write_buffer = 2M [mysqlhotcopy] interactive-timeout [root@sql mysql]# NETSTAT on Web Server ################################# I have changed acutal IP to WEBSERVERIP ( for the webserver ) and DBSERVERIP ( for the db server ip ) [root@web temphotos]# netstat -an | grep DBSERVERIP tcp 0 0 WEBSERVERIP:57666 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:54315 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:53293 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53295 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53305 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53304 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53307 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53306 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53309 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53308 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53311 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53310 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53297 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53296 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53299 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53298 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53301 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53300 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53303 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53302 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53257 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53256 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53259 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53258 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53462 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:56250 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:50288 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:52286 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:53116 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:48573 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:48574 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:48575 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:48568 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:48569 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:48570 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:48571 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:48300 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:47460 DBSERVERIP:3306 TIME_WAIT tcp 0 0 WEBSERVERIP:42983 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:44035 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:44974 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:43896 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:37081 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:40781 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:36109 DBSERVERIP:3306 ESTABLISHED tcp 0 0 WEBSERVERIP:35119 DBSERVERIP:3306 ESTABLISHED [root@web temphotos]# Lots of TIME_WAIT , i have truncated the logs. Both servers have 1000M interface and db server has 3G ram 2cpu @ 2.27GHz (Intel(R) Xeon(R) CPU). Sql server is not loaded at all , infact load never goes beyond 1. Can you advise how can we get rid of TIME_WAIT or is this normal? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
