Re: squid 2.3. Stable4 Performance issues

There are several possible explanations:

 * A new bug
 * A old bug which did not manifest itself while you ran 2.2, but is now
a problem due to a slight change in the usage pattern (sites/content
retreived by your users)
 * Only a measurement ghost, caused by a sudden burst of slow HTTP
requests (usualy robots going wild, trying to retreive content where the
server is not reachable)

Quick check: Do you also have memory usage graphs of the same time?
There are a couple of known memory usage issues in 2.3 (and 2.2 for that
matters), which only shows up in very specific usage patterns. (see
http://squid.sourceforge.net/hno/patch-2.3.html). When the memory usage
grows high, response times will collapse. Most of these issues are in
such nature that the memory usage is only temporary (couple of hours,
depending on the user), and shows up as a significant saw-tooth pattern
in memory usage graphs.

Quick check 2: Do you see any anomalities in access.log and/or cache.log
when it happens?

Quick check 3: Other than the measurement, was there any noticed
response slowdown?

Quick check 4: Do you also have graphs of hit response times?

--
Henrik Nordstrom
Squid hacker
Patrice ARNAL wrote:
> 
> Hello
> 
> I installed a squid 2.3. Stable 4 on a sun Ultra 250 under sunOS 5.6
> 
> I noticed a regular slowdown of the response time with sometimes a
> sudden collapse of this response time.
> 
> With the MRTG monitor of my squid, I noticed that the HTTP Median
> Service Time went up to 600ms instead of the 10ms I expected
> ( see the attached graph)
> 
> A squid -k shutdown followed by a restart of squid solved the problem
> 
> This never happend with the squid 2.2 Stable 4 I used before.
> It runned sevveral months without performance problems other than DNS
> requests slow downs.
> 
>     ---------------------------------------------------------------
>  [Image]
--
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