ivelin 2002/10/13 08:09:54
Modified: src/documentation/xdocs performancetips.xml
Log:
document the pipeline "expires" parameter
Revision Changes Path
1.9 +54 -0 xml-cocoon2/src/documentation/xdocs/performancetips.xml
Index: performancetips.xml
===================================================================
RCS file: /home/cvs/xml-cocoon2/src/documentation/xdocs/performancetips.xml,v
retrieving revision 1.8
retrieving revision 1.9
diff -u -r1.8 -r1.9
--- performancetips.xml 12 Aug 2002 21:55:46 -0000 1.8
+++ performancetips.xml 13 Oct 2002 15:09:54 -0000 1.9
@@ -94,6 +94,51 @@
take more time to process them. In worst case scenario, slowdown up to
10% could be achieved (unscientifical observations, do your own
test).</li>
+
+ <li>
+ <p>
+ Utilize the pipeline <code>expires</code> parameter to dramatically
reduce
+ redundand requests. Even the most dynamic application pages have a
+ reasonable period of time during which they are static.
+ Even if a page doesn't change for just one minute, still use the
+ <code>expires</code> parameter. Here is an example:
+ </p>
+<source><![CDATA[
+<map:pipeline>
+ <map:parameter name="expires" value="access plus 1 minutes"/>
+ ...
+</map:pipeline>
+]]></source>
+ <p>
+ The value of the parameter is in a format borrowed from the Apache
HTTP module mod_expires.
+ Examples of other possible values are:
+ </p>
+<source><![CDATA[
+access plus 1 hours
+access plus 1 month
+access plus 4 weeks
+access plus 30 days
+access plus 1 month 15 days 2 hours
+]]></source>
+ <p>
+ Imagine 1'000 users hitting your web site at the same time.
+ Say that they are split into 5 groups, each of which has the same ISP.
+ Most ISPs use intermediate proxy servers to reduce traffic, hense
+ improving their end user experience and also reducing their operating
costs.
+ In our case the 1'000 end user requests will result in just 5 requests
to Cocoon.
+ </p>
+ <p>
+ After the first request from each group reaches the server, the
expires header will
+ be recognized by the proxy servers which will serve the following
requests from their cache.
+ Keep in mind however that most proxies cache HTTP GET requests, but
will not cache HTTP POST requests.
+ </p>
+ <p>
+ To feel the difference, set an expires parameter on one of your
pipelines and
+ load the page with the browser. Notice that after the first time,
there are no
+ access records in the server logs until the specified time expires.
+ </p>
+
+ </li>
</ul>
</s1>
@@ -143,6 +188,10 @@
<li>Try to keep the size of the documents going through the pipeline
small. To big documents slows down translation.</li>
+
+ <li>Use the <code>expires</code> parameter (see above) as frequently as you
can.
+ It improves the end user experience dramatically. Browsers and
intermediate
+ proxy servers love the HTTP <code>Expires</code> header.</li>
</ul>
</s1>
@@ -184,6 +233,11 @@
<li>How complicated are the XSLT stylesheets? If you are not using global
variables or parameters this will speeds things up.</li>
+
+ <li>Consider using XSLTC instead of Xalan. XSLTC compiles XSLT to bytecode
(translets)
+ the first time a stylesheet is used. Consequently it uses the compiled code
+ which is faster by a magnitude than the interpreted one.</li>
+
</ul>
</s1>
</body>
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