changes-2.0.4-2.0.5.xml

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<group from="2.0.4" to="2.0.5">
  <subsystem>
    <name>varnishd</name>

    <change type="bug" ref="498">
      <para>Handle object workspace overruns better.</para>
    </change>

    <change type="enh">
      <para>Allow turning off ESI processing per request by using
      <code>set req.esi = off</code>.</para>
    </change>

    <change type="enh">
      <para>Tell the kernel that we expect to use the mmap-ed file in
      a random fashion.  On Linux, this turns off/down readahead and
      increases performance.</para>
    </change>

    <change type="enh">
      <para>Make it possible to change the maximum number of HTTP
      headers we allow by
      passing <code>--with-max-header-fields=NUM</code> rather than
      changing the code.</para>
    </change>

    <change type="enh" ref="428">
      <para>Implement support for HTTP continuation lines.</para>
    </change>

    <change type="enh">
      <para>Change how connections are closed and only use SO_LINGER
      for orderly connection closure.  This should hopefully make
      worker threads less prone to hangups on network problems.</para>
    </change>

    <change type="bug" ref="502">
      <para>Handle multi-element purges correctly.  Previously we
      ended up with parse errors when this was done from VCL.</para>
    </change>

    <change type="bug" ref="506, 549">
      <para>Handle illegal responses from the backend better by
      serving a 503 page rather than panic-ing.</para>
    </change>

    <change type="enh">
      <para>When we run into an assertion that is not true, Varnish
      would previously dump a little bit of information about itself.
      Extend that information with a backtrace.  Note that this relies
      on the varnish binary being unstripped.</para>
    </change>

    <change type="enh">
      <para>Add a session_max parameter that limits the maximum
      number of sessions we keep open before we start dropping new
      connections summarily.</para>
    </change>

    <change type="bug">
      <para>Try to consume less memory when doing ESI processing by
      properly rolling back used workspace after processing an
      object.  This should make it possible to
      turn <code>sess_workspace</code> quite a bit for users with
      ESI-heavy pages.</para>
    </change>

    <change type="enh">
      <para>Turn on <code>session_linger</code> by default.  Tests
      have shown that <code>session_linger</code> helps a fair bit
      with performance.</para>
    </change>

    <change type="enh">
      <para>Rewrite the epoll acceptor for better performance.  This
      should lead to both higher processing rates and maximum number
      of connections on Linux.</para>
    </change>

    <change type="enh">
      <para>Add If-None-Match support, this gives significant
      bandwidth savings for users with compliant browsers.</para>
    </change>

    <change type="bug" ref="529">
      <para>RFC2616 specifies
      that <code>ETag</code>, <code>Content-Location</code>, <code>Expires</code>, <code>Cache-Control</code>
      and <code>Vary</code> should be emitted when delivering a
      response with the 304 response code.</para>
    </change>

    <change type="bug" ref="531">
      <para>Various fixes which makes Varnish compile and work on AIX.</para>
    </change>

    <change type="enh">
      <para>Turn on TCP_DEFER_ACCEPT on Linux.  This should make us
      less suspecible to denial of service attacks as well as give us
      slightly better performance.</para>
    </change>

    <change type="enh">
      <para>Add an <code>.initial</code> property to the backend
      probe specification.  This is the number of good probes we
      pretend to have seen.  The default is one less than .threshold,
      which means the first probe will decide if we consider the
      backend healthy.</para>
    </change>

    <change type="enh">
      <para>Make it possible to compare strings against other
      string-like objects, not just plain strings.  This allows you to
      compare two headers, for instance.</para>
    </change>

    <change type="bug">
      <para>When support for <code>restart</code>
      in <code>vcl_error</code> was added, there was no check to
      prevent infinte recursion.  This has now been fixed.
     </para>
    </change>

    <change type="enh">
      <para>Turn on purge_dups by default.  This should make us
      consume less memory when there are many bans for the same
      pattern added.</para>
    </change>

    <change type="enh">
      <para>Add a new log tag called <code>FetchError</code> which
      tries to explain why we could not fetch an object from the
      backend.</para>
    </change>

    <change type="enh">
      <para>Change the default <code>srcaddr_ttl</code> to 0.  It is
      not used by anything and has been removed in the development
      version.  This will increase performance somewhat.</para>
    </change>

  </subsystem>

  <subsystem>
    <name>varnishtop</name>
    <change type="bug" ref="514">
      <para>varnishtop did not handle variable-length log fields
      correctly. This is now fixed.</para>
    </change>

    <change type="enh">
      <para>varnishtop previously did not print the name of the tag,
      which made it very hard to understand.  We now print out the
      tag name.</para>
    </change>
  </subsystem>
</group>