Re: [AMaViS-user] timeout after END-OF-MESSAGE

[Mark M. <Mar...@ij...>]

Seba,

> since I've installed amavisd-new 2.6.0 I get these error messages in my
> mail log:
>
> May 22 01:05:18 mail postfix/anvil[2770]: statistics: max cache size 1 at
> May 22 01:01:52 May 22 01:06:56 mail postfix/smtpd[2775]: timeout after
> END-OF-MESSAGE from localhost[127.0.0.1] May 22 01:06:56 mail
> postfix/smtpd[2775]: disconnect from localhost[127.0.0.1] May 22 01:06:58
> mail postfix/smtpd[2792]: timeout after END-OF-MESSAGE from
> localhost[127.0.0.1] May 22 01:06:58 mail postfix/smtpd[2792]: disconnect
> from localhost[127.0.0.1]
>
> Same problem that is described here:
> http://sourceforge.net/mailarchive/message.php?msg_id=4816D754.8030704%40ca
>f.com.tr
>
> I'm using Postfix 2.5.1 with amavisd-new as content-filter (defined in
> main.cf).

A result of connection caching when it happens the session is held
in hope for a next task, which doesn't come soon enough.
No harm done. The feature can be disabled for low traffic sites.


From release notes:

- smtp client connection caching is a new feature which allows smtp client
  code in amavisd to keep a SMTP session to MTA open after forwarding a
  message or a notification, so that a next mail message that needs to be
  sent by this child process can avoid re-establishing a session and the
  initial greeting/EHLO (and TLS) handshake.

  A current value of a global settings $smtp_connection_cache_enable
  controls whether a session will be retained after forwarding a message
  or not. Its default initial value is true.

  A global setting $smtp_connection_cache_on_demand controls whether amavisd
  is allowed to dynamically change the $smtp_connection_cache_enable setting
  according to its estimate of the message frequency. The heuristics is
  currently very simple: if time interval between a previous task completion
  by this child process and the arrival of a current message is 5 seconds
  or less, the $smtp_connection_cache_enable is turned on (which will affect
  the next message); if the interval is 15 seconds or more, it is turned off.
  The default value of the $smtp_connection_cache_on_demand is true, thus
  enabling the adaptive behaviour.

  On a busy server the connection caching can save some processing time.
  Savings are substantial if client-side TLS is enabled, otherwise just a
  few milliseconds are saved. On an idle server the feature may unnecessarily
  keep sessions to MTA open (until MTA times them out), so one can disable
  the feature by setting both controls to false (to 0 or undef).

  To monitor the connection caching effectiveness, some SNMP-like counters
  were added, so amavisd-agent may display something like:

    OutConnNew                      2764    319/h    98.2 % (OutMsgs)
    OutConnQuit                     2521    291/h    89.5 % (OutMsgs)
    OutConnReuseFail                   7      1/h     0.2 % (OutMsgs)
    OutConnReuseRecent                21      2/h     0.7 % (OutMsgs)
    OutConnReuseRefreshed             31      4/h     1.1 % (OutMsgs)
    OutConnTransact                 2816    325/h   100.0 % (OutMsgs)


Mark