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<!DOCTYPE modulesynopsis SYSTEM "/style/modulesynopsis.dtd">

<?xml-stylesheet type="text/xsl" href="/style/manual.en.xsl"?>

<modulesynopsis metafile="mpm_winnt.xml.meta">

<name>mpm_winnt</name>

<description>Multi-Processing Module optimized for Windows NT.</description>

<status>MPM</status>

<sourcefile>mpm_winnt.c</sourcefile>

<identifier>mpm_winnt_module</identifier>

<summary>

<p>This Multi-Processing Module (MPM) is the default for the

Windows NT operating systems. It uses a single control process

which launches a single child process which in turn creates

threads to handle requests</p>

<p>Capacity is configured using the

<directive module="mpm_common">ThreadsPerChild</directive> directive,

which sets the maximum number of concurrent client connections.</p>

<p>By default, this MPM uses advanced Windows APIs for accepting

new client connections. In some configurations, third-party products

may interfere with this implementation, with the following messages

written to the web server log:</p>

<example>

Child: Encountered too many AcceptEx faults accepting client connections.<br />

winnt_mpm: falling back to 'AcceptFilter none'.

</example>

<p>The MPM falls back to a safer implementation, but some client requests

were not processed correctly. In order to avoid this error, use

<directive module="core">AcceptFilter</directive> with accept filter

<code>none</code>.</p>

<highlight language="config">

AcceptFilter http none

AcceptFilter https none

</highlight>

<p><em>In Apache httpd 2.0 and 2.2,

<directive>Win32DisableAcceptEx</directive> was used for this purpose.</em></p>

<p>The WinNT MPM differs from the Unix MPMs such as worker and event

in several areas:</p>

<ul>

<li>When a child process is exiting due to shutdown, restart, or

<directive module="mpm_common">MaxConnectionsPerChild</directive>,

active requests in the exiting process have

<directive module="core">TimeOut</directive> seconds to finish before

processing is aborted. Alternate types of restart and shutdown are not

implemented.</li>

<li>New child processes read the configuration files instead of

inheriting the configuration from the parent. The behavior will

be the same as on Unix if the child process is created at startup

or restart, but if a child process is created because the prior

one crashed or reached

<directive module="mpm_common">MaxConnectionsPerChild</directive>,

any pending changes to the configuration will become active in the

child at that point, and the parent and child will be using a

different configuration. If planned configuration changes have been

partially implemented and the current configuration cannot be

parsed, the replacement child process cannot start up and the server

will halt. Because of this behavior, configuration files should not

be changed until the time of a server restart.</li>

<li>The <code>monitor</code> and <code>fatal_exception</code> hooks

are not currently implemented.</li>

<li><directive>AcceptFilter</directive> is implemented in the MPM

and has a different type of control over handling of new connections.

(Refer to the <directive module="core">AcceptFilter</directive>

documentation for details.)</li>

</ul>

</summary>

<seealso><a href="/platform/windows.html">Using Apache HTTP Server on Microsoft Windows</a></seealso>

<directivesynopsis location="core"><name>AcceptFilter</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>CoreDumpDirectory</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>PidFile</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>Listen</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>ListenBacklog</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>MaxConnectionsPerChild</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>MaxMemFree</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>ScoreBoardFile</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>ReceiveBufferSize</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>SendBufferSize</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>ThreadLimit</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>ThreadsPerChild</name>

</directivesynopsis>

<directivesynopsis location="mpm_common"><name>ThreadStackSize</name>

</directivesynopsis>

</modulesynopsis>