Re: Observation about icp_query_timeout in Squid 2

From: Alex Rousskov <rousskov@dont-contact.us>
Date: Tue, 1 Dec 1998 10:53:27 -0700 (MST)

On Tue, 1 Dec 1998, Chris Teakle wrote:

> Putting squid into debug mode revealed that ICP queries were being
> given very low timeouts, often well under 100ms. Thus squid was all too
> often giving up on its peers and going direct.
>
> When I set icp_query_timeout to 1000 (ms), the TIMEOUT_DIRECT fetches
> virtually disappeared and the direct fetches dropped back to around 30%
> (In fact a value of 250ms gave much the same result.)
>
> It seems to me that something must be wrong with the automatic timeout
> calculation for it to consistently underestimate so badly.

What is your definition of an optimal timeout?

IMO, if the machines are in the same room, 100ms is a "long enough" time to
answer an ICP query, unless your caches are overloaded. Clearly, the built-in
algorithm cannot guess right all the time in all the environments. That is
why you have an option to set the timeout manually, I guess.

Alex.
Received on Tue Dec 01 1998 - 11:11:36 MST

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