Re: [squid-users] Elapsed time for HTTPS requests

On 13/08/11 01:26, Nitin Chandrachoodan wrote:
> Hello,
>
> I am running squid-2.7.STABLE7 and we are experiencing poor
> performance (very slow page loads, timeouts etc.). This is in a large
> campus setting with a few thousand users. One observation is that the
> elapsed time for HTTPS CONNECT operations looks like below. Are these
> numbers normal, or too high? Over longer durations, I find many values
> clustered around 60000, 120000, 240000 etc., which makes me suspect
> timeouts. The elapsed times for GET and POST are better.
>
> For example
> $ sudo tail -f /var/log/squid/access.log | grep CONNECT
> 1313146579.775 215331 10.91.0.31 TCP_MISS/200 27133 CONNECT
> s.yimg.com:443 - DIRECT/118.214.109.227 -
> 1313146579.775 215346 10.91.0.31 TCP_MISS/200 34679 CONNECT
> s.yimg.com:443 - DIRECT/118.214.109.227 -
<snip>
>
> As you can see, the elapsed time for CONNECT (~81s average) is far
> higher than the others (about 3-4s average). Is this just due to
> connections being kept alive, or is there something else
> likely wrong? Also, do the average numbers for the others look normal
> or are they too high?

keep-alive is not related to any of this. The measure in your log is for
the transafer of that individual HTTP request.

What you need to know is that GET/POST etc are individual object
transfers and only last as long as it takes the server to generate and
transfer the object bytes across.

CONNECT is different. A binary tunnel. There are no actual limits on
what can be inside or when that will finish. For port 443 tunnels each
one usually has many encrypted requests going on inside it behind the
encryption. The duration lasts as long as the things inside require.

I can't really speak to whether those sizes are normal. But a few
minutes hardly seems out of place considering the above. Depends on how
ling the client is browsing a particular HTTPS website.

Amos

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