Hi, > It sounds like you're more interested in the number of active connections that can be > maintained, in which case the max_connections variable is likely to be of more use to you.
I set the variables max_connections to 700 and back_log to 600. My server can maintain it. The problem that I want identified is which server between MySQL server and HTTP server has limit to handle the maximun number of connections that it can do to interact with another one. Also the MySQL server has during the periodes of strong load less than 420 connections. The CPUs (2 CPUs) and memory (up to 2.5 Gb) utilisation are correct when it happens. I rarely have a so pretty busy MySQL server. The HTTP server has lot of CPU (1 CPU) and memory (up to 3 Gb) resources available while it reached the maximun number of clients. But in this server (HTTP), it often happens that it cannot treat any more the connections requests to the MySQL server or connections responses from the MySQL server. And in this case it is blocked for a while. to resolve this, I often restart the httpd (daemon) to resolve blocking state. That is why I suspect the system resource <listen queue size> to can be the bottleneck. Any advice will be appreciated think in advance -----Original Message----- From: Paul DuBois [mailto:[EMAIL PROTECTED] Sent: mercredi 30 juillet 2003 15:21 To: Thierno Cissé Cc: [EMAIL PROTECTED] Subject: RE: how listen queue size affect MySQL on RedHat At 14:55 +0000 7/30/03, Thierno Cissé wrote: >Hi Paul Dubois, Please reply to the list, not just to me directly. Thanks. >we late to answers due to administration problems. >> MySQL doesn't have anything to do with HTTP connections. >Next is an extract of MySQL documentation (MySQL reference manual up to >Version 4.1.0-alpha). > >...In other words, this value is the size of the listen queue for >incoming TCP/IP connections. Your operating system has its own limit on >the size of this queue. The manual >page for the Unix listen(2) system call should have more details. Check >your OS >documentation for the maximum value for this variable. Attempting to set >back_log >higher than your operating system limit will be ine®ective. > >And , in relation to back_log=600 variable in my my.cnf file, I want to >know if there is an effect to setting this variable with a value higher >that system parameter >listen queue size ? >This response will help to determine the causes of bugs which appears >in our web site as soon as apache HTTP processes which interact with >MySQL server >tends to higher value like 300-400 process . >Think in advance back_log refers to the size of the queue for connections that have not yet been accepted (though the precise semantics for this may depend on your operating system. For example, the meaning of "queued" on Linux appears to have changed with Linux 2.2, according to my listen(2) manpagge.) It sounds like you're more interested in the number of active connections that can be maintained, in which case the max_connections variable is likely to be of more use to you. With respect to setting back_log higher than the value allowed by your operating system, it's just as the MySQL manual says: Setting it higher than the OS limit won't get you anything. (How could it? The OS won't let you exceed its own limit.) Also, it's not clear from your message whether the "bugs" to which you allude above are problems with your web server (and its connections), or connections between your web server and your MySQL server... depends on what symptoms you're observing. > >-----Original Message----- >From: Paul DuBois [mailto:[EMAIL PROTECTED] >Sent: mercredi 30 juillet 2003 04:44 >To: [EMAIL PROTECTED]; [EMAIL PROTECTED] >Subject: Re: how listen queue size affect MySQL on RedHat > > >At 14:53 +0000 7/29/03, <[EMAIL PROTECTED]> wrote: >>Hi all, >>i want to know if the system parameter somaxconn affect the >>capabalities of MySQL to maintain more than five thousands of HTTP >>connections ? If so , any clarifications may help. think in advance > >MySQL doesn't have anything to do with HTTP connections. >What are you really asking? -- Paul DuBois, Senior Technical Writer Madison, Wisconsin, USA MySQL AB, www.mysql.com Are you MySQL certified? http://www.mysql.com/certification/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
