[squid-users] Need clarifications on custom log timestamps

[Alex Rousskov]

On 2025-02-26 01:58, Amos Jeffries wrote:
> On 26/02/25 00:33, BENJAMIN DELANNOY wrote:
>>  > Please detail what you mean by "choice" or "decision". For example, do
>>> you want to stop the timer when Squid makes its final http_access 
>>> decision?
>>
>> I mean I want to monitor the latency on what I could manage : the 
>> communication between client & squid, the time squid uses to process 
>> requests. But not the time spent by the destination server as I don't 
>> manage it.
>> This could be multiple monitors if 1 is too complicated or not 
>> possible. So yes for example a timer that stop when Squid makes its 
>> final http_access decision (in case of http or bumped https) or its 
>> final ssl_bump splice decision.
>>
> 
> In theory what you want is the %busy_time logformat.

Please note that %busy_time

* includes the time spent on origin server-driven work (which Benjamin 
may want to _exclude_) and

* excludes the time spent waiting for client I/O (which Benjamin may 
want to _include_).

Alex.


> However, the calculations for that are still apparently inaccurate. So 
> you would be best also logging these for comparison measures:
> 
>   %dt = DNS latency
> 
>   %<tt - %<pt = forwarding-latency
>      .. the time spent by Squid fetching the response.
>      .. excluding time waiting for it to arrive from the upstream server
>      .. also excluding anything that happens while the server is 
> delivering response (eg. for responses >4KB).
> 
>   %tr - %<pt = total Squid latency
>      .. including delays from parallel traffic
>      .. excluding same as forwarding-latency above
> 
> 
> HTH
> Amos
> 
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