added $MainMsgQueueSize config directive

1 files changed, 21 insertions, 0 deletions

diff --git a/doc/rsyslog_conf.html b/doc/rsyslog_conf.html
index 8246edf7..c19c4736 100644
--- a/doc/rsyslog_conf.html
+++ b/doc/rsyslog_conf.html
@@ -302,6 +302,27 @@ will not be applied to configuration lines following the $ResetConfigVariables.
 This is a good method to make sure no side-effects exists from previous 
 directives. This directive has no parameters.</p>
 <p><code><b>$ResetConfigVariables</b></code></p>
+<h2>MainMsgQueueSize</h2>
+<p>This allows to specify the maximum size of the message queue. This directive 
+is only available when rsyslogd has been compiled with multithreading support. 
+In this mode, receiver and output modules are de-coupled via an in-memory queue. 
+This queue buffers messages when the output modules are not capable to process 
+them as fast as they are received. Once the queue size is exhausted, messages 
+will be dropped. The slower the output (e.g. MySQL), the larger the queue should 
+be. Buffer space for the actual queue entries is allocated on an as-needed 
+basis. Please keep in mind that a very large queue may exhaust available system 
+memory and swap space. Keep this in mind when configuring the max size. The 
+actual size of a message depends largely on its content and the orginator. As a 
+rule of thumb, typically messages should not take up more then roughtly 1k (this 
+is the memory structure, not what you see in a network dump!). For typical linux 
+messages, 512 bytes should be a good bet. Please also note that there is a 
+minimal amout of memory taken for each queue entry, no matter if it is used or 
+not. This is one pointer value, so on 32bit systems, it should typically be 4 
+bytes and on 64bit systems it should typically be 8 bytes. For example, the 
+default queue size of 10,000 entries needs roughly 40k fixed overhead on a 32 
+bit system. </p>
+<p><code><b>$MainMsgQueueSize 100000 # 100,000 may be a value to handle bursty 
+traffic</b></code></p>
 <h2>ModLoad</h2>
 <p>This currently is a dummy directive. It will support the loading of plug-ins 
 in future releases of rsyslog supporting plug-ins. Currently, only</p>