[squid-users] Seeking insight into zeros, negative values in log: 2.6.STABLE18

[Henry S. Thompson]

Amos Jeffries writes:

> On 5/08/2016 12:37 a.m., Henry S. Thompson wrote:
>> Thanks for your patience with this, but still not quite getting it.
>> 
>> I thought there were two cases:
>> 
>>   1) Client drops the connection before the interaction is complete ==
>>      log shows HTTP result code 000, almost always size 0 as well;
>> 
>>   2) Interaction completed successfully == HTTP result code as from
>>      cache or remote, size as sent to client.
>> 
>> See below how I can't make that fit with your reply
>
> #1 is correct but incomplete. The 000 status means dropped any time
> before the status to be delivered became known. So while "incomplete" is
> true, there are very short times in the transaction where "incomplete"
> is still true but are logged with non-000 status and size 0.
>
> NP: There are also later times during payload delivery where drop can
> happen so incomplete is still true and both status and size have values.
> Those are impossible to detect in HTTP/1.0, so another reason to upgrade
> to HTTP/1.1 software (Squid-3.2+).

So is this a correct summary:

  Log shows size 0 iff client dropped the connection before the
  interaction was complete (HTTP result code 000 vs. something else is
  just a question of when the drop was detected);

  In other words, 0 size in the log can _never_ mean all is well, server
  result was empty, because if all is well at least some header info
  will have been sent.

ht
-- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 650-4587, e-mail: ht at inf.ed.ac.uk
                       URL: http://www.ltg.ed.ac.uk/~ht/
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