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| <h1 align="CENTER">Multi-Processing Module worker</h1> |
| |
| <p>This Multi-Processing Module implements a hybrid |
| multi-threaded multi-process web server.</p> |
| |
| <p><a href="module-dict.html#Status" |
| rel="Help"><strong>Status:</strong></a> MPM<br /> |
| <a href="module-dict.html#SourceFile" |
| rel="Help"><strong>Source File:</strong></a> worker.c<br /> |
| <a href="module-dict.html#ModuleIdentifier" |
| rel="Help"><strong>Module Identifier:</strong></a> |
| mpm_worker_module</p> |
| |
| <h2>Summary</h2> |
| |
| <p>This Multi-Processing Module (MPM) is the default for most |
| unix-like operating systems. It implements a hybrid |
| multi-process multi-threaded server. Each process has a fixed |
| number of threads. The server adjusts to handle load by |
| increasing or decreasing the number of processes.</p> |
| |
| <p>A single control process is responsible for launching child |
| processes. Each child process creates a fixed number of threads |
| as specified in the <code>ThreadsPerChild</code> directive. The |
| individual threads then listen for connections and serve them |
| when they arrive.</p> |
| |
| <p>Apache always tries to maintain a pool of <em>spare</em> or |
| idle server threads, which stand ready to serve incoming |
| requests. In this way, clients do not need to wait for a new |
| threads or processes to be created before their requests can be |
| served. Apache assesses the total number of idle threads in all |
| processes, and forks or kills processes to keep this number |
| within the boundaries specified by <code>MinSpareThreads</code> |
| and <code>MaxSpareThreads</code>. Since this process is very |
| self-regulating, it is rarely necessary to modify these |
| directives from their default values. The maximum number of |
| clients that may be served simultaneously is determined by |
| multiplying the maximum number of server processes that will be |
| created (<code>MaxClients</code>) by the number of threads |
| created in each process (<code>ThreadsPerChild</code>).</p> |
| |
| <p>While the parent process is usually started as root under |
| Unix in order to bind to port 80, the child processes and |
| threads are launched by Apache as a less-privileged user. The |
| <code>User</code> and <code>Group</code> directives are used to |
| set the privileges of the Apache child processes. The child |
| processes must be able to read all the content that will be |
| served, but should have as few privileges beyond that as |
| possible. In addition, unless <a |
| href="../suexec.html">suexec</a> is used, these directives also |
| set the privileges which will be inherited by CGI scripts.</p> |
| |
| <p><code>MaxRequestsPerChild</code> controls how frequently the |
| server recycles processes by killing old ones and launching new |
| ones.</p> |
| |
| <p>See also: <a href="../bind.html">Setting which addresses and |
| ports Apache uses</a>.</p> |
| |
| <h2>Directives</h2> |
| |
| <ul> |
| <li><a |
| href="mpm_common.html#coredumpdirectory">CoreDumpDirectory</a></li> |
| |
| <li><a href="mpm_common.html#group">Group</a></li> |
| |
| <li><a href="mpm_common.html#pidfile">PidFile</a></li> |
| |
| <li><a href="mpm_common.html#listen">Listen</a></li> |
| |
| <li><a |
| href="mpm_common.html#listenbacklog">ListenBacklog</a></li> |
| |
| <li><a href="mpm_common.html#lockfile">LockFile</a></li> |
| |
| <li><a href="mpm_common.html#maxclients">MaxClients</a></li> |
| |
| <li><a |
| href="mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></li> |
| |
| <li><a |
| href="mpm_common.html#maxsparethreads">MaxSpareThreads</a></li> |
| |
| <li><a |
| href="mpm_common.html#minsparethreads">MinSpareThreads</a></li> |
| |
| <li><a |
| href="mpm_common.html#scoreboardfile">ScoreBoardFile</a></li> |
| |
| <li><a |
| href="mpm_common.html#sendbuffersize">SendBufferSize</a></li> |
| |
| <li><a |
| href="mpm_common.html#startservers">StartServers</a></li> |
| |
| <li><a |
| href="mpm_common.html#threadsperchild">ThreadsPerChild</a></li> |
| |
| <li><a href="mpm_common.html#user">User</a></li> |
| </ul> |
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