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From jcor...@apache.org
Subject svn commit: r1494829 - /subversion/site/publish/docs/release-notes/1.8.html
Date Thu, 20 Jun 2013 01:09:20 GMT
Author: jcorvel
Date: Thu Jun 20 01:09:20 2013
New Revision: 1494829

URL: http://svn.apache.org/r1494829
Log:
Add information about serf skelta mode and the configuration knobs involved
to the 1.8 release notes.

Patch by: lgo
          (tweaked by me)

Modified:
    subversion/site/publish/docs/release-notes/1.8.html

Modified: subversion/site/publish/docs/release-notes/1.8.html
URL: http://svn.apache.org/viewvc/subversion/site/publish/docs/release-notes/1.8.html?rev=1494829&r1=1494828&r2=1494829&view=diff
==============================================================================
--- subversion/site/publish/docs/release-notes/1.8.html (original)
+++ subversion/site/publish/docs/release-notes/1.8.html Thu Jun 20 01:09:20 2013
@@ -401,24 +401,124 @@ TCP connections to the server.
 Clients using neon will also work fine with this configuration.</p>
 </div>
 
-<div class="h4" id="serf-server-log">
-<h4>Server logs larger with serf clients
-  <a class="sectionlink" href="#serf-server-log"
+<div class="h4" id="serf-skelta-default">
+<h4>Skelta style updates are now the default
+  <a class="sectionlink" href="#serf-skelta-default"
     title="Link to this section">&para;</a>
 </h4>
 
-<p><em>This affects any server version, when accessed with a 1.8
-client.</em></p>
+<p>The svn 1.8 client with serf defaults to skelta mode for update
+operations (checkout, update, merge and export) instead of the bulk update mode
+used by previous versions. Skelta mode was introduced in Subversion 1.6.0 and
+improved in 1.8.0. It uses one HTTP request and response per resource that needs
+to be fetched from the server, whereas bulk update mode fetches all resources in
+one massive reponse.</p>
+
+<p>The main benefit of skelta mode is that it allows a correctly set up Apache
+server or intermediate proxy server to cache <tt>mod_dav_svn</tt>’s responses
to
+handle later requests from the cache. This results in improved performance of
+svn client operations and reduced CPU usage on the server side. It also allows
+a more detailed audit of clients accessing resources in a Subversion
+repository.</p>
 
-<p>Because serf clients issue a larger number of HTTP GET requests
-than neon clients it is possible that serf clients cause quicker
-growth of httpd server logs than neon clients do. As of 1.7.3, 
-the httpd error logs may also grow more rapidly with serf clients
-than with neon clients; see
+<p>Skelta mode has some disadvantages:</p>
+<ul>
+<li>Apache server access log files will grow more quickly due to the larger
+number of requests and responses. As of 1.7.3, the httpd error logs may also
+grow more rapidly with serf clients than with neon clients; see
 <a href="http://svn.apache.org/viewvc?rev=1239697&amp;view=rev"
->r1239697</a>.</p>
+>r1239697</a>.</li>
+<li>Network traffic can increase drastically when Kerberos or NTLM
+authentication is used, as these add a 2 - 4 KB header per HTTP request and
+response.</li>
+</ul>
+
+<p>This release introduces two options to control if the svn client will use
+skelta or bulk update mode.</p>
+<p>
+<ul>
+<li> For the server administrator: The <tt>SVNAllowBulkUpdates</tt> directive
for
+<tt>mod_dav_svn</tt> now accepts <tt>Prefer</tt>. This will advise
the svn
+client to always use bulk update mode. All svn client versions with a default
+configuration (see table) will respect this preference.</li>
+
+<li>For the user: Set the new option <tt>http-bulk-updates</tt> in the
servers
+runtime configuration file to <em>yes</em> to force the use of bulk updates,
+<em>no</em> to never use bulk updates. The default option <em>auto</em>
makes
+svn use skelta mode with a 1.8 server (unless it has <tt>SVNAllowBulkUpdates</tt>
+set to <tt>Prefer</tt>), and bulk updates mode with
+older servers and 1.8 servers which prefer bulk updates.</li>
+</ul>
+</p>
+
+<div class="notice">
+<p>For 1.8 servers, set <strong>SVNAllowBulkUpdates</strong> to
+<strong>Prefer</strong> if your server configuration does not allow an
+intermediate caching server - on your side or on the client's side - to
+successfully cache server responses.</p>
+</div>
+
+<p>Table explaining the mode used between each combination of svn client and
+server version and relevant configuration directives:</p>
+
+<table border="1">
+  <tr>
+    <th></th>
+    <th colspan="3">1.8 Server<br/>with SVNAllowBulkUpdates:</th>
+    <th colspan="2">1.7 and older Server<br/>with SVNAllowBulkUpdates:</th>
+  </tr>
+  <tr>
+    <th>Subversion Client</th>
+    <th>Off</th>
+    <th>On<sup>*</sup></th>
+    <th>Prefer</th>
+    <th>Off</th>
+    <th>On<sup>*</sup></th>
+  </tr>
+  <tr>
+    <td>1.8, <tt>http-bulk-updates: auto</tt><sup>*</sup></td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+    <td>Bulk mode</td>
+    <td>Skelta mode</td>
+    <td>Bulk mode</td>
+  </tr>
+  <tr>
+    <td>1.8, <tt>http-bulk-updates: yes</tt></td>
+    <td>Skelta mode</td>
+    <td>Bulk mode</td>
+    <td>Bulk mode</td>
+    <td>Skelta mode</td>
+    <td>Bulk mode</td>
+  </tr>
+  <tr>
+    <td>1.8, <tt>http-bulk-updates: no</tt></td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+  </tr>
+  <tr>
+    <td>1.7 and older with neon<sup>*</sup></td>
+    <td>Skelta mode</td>
+    <td>Bulk mode</td>
+    <td>Bulk mode</td>
+    <td>Skelta mode</td>
+    <td>Bulk mode</td>
+  </tr>
+  <tr>
+    <td>1.7 and older with serf</td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+    <td>Skelta mode</td>
+  </tr>
+</table>
+<p><sup>*</sup>Default configuration</p>
 
-</div>  <!-- serf-server-log -->
+</div>  <!-- serf-skelta-default -->
 
 </div>  <!-- neon-deleted -->
 



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