Re: [squid-users] is this possible?

botemout_at_gmail.com wrote:
> Thanks for the hint.
>
> I'm using the collapsed_forwarding and quick_abort_* options and seem to
> be having some luck. There are, however, oddities. It seems that
> sometimes additional requests are still being forwarded to the
> underlying web server. Other than "squidclient mgr:active_requests" are
> there any other ways of monitoring the status of subsequent requests
> which should be deferred to wait for the original?

A quick look about and I can't find anything in Squid sorry.

Amos

>
> thanks
>
> JR
>
> Amos Jeffries wrote:
>> botemout_at_gmail.com wrote:
>>> Greetings
>>>
>>> We have an unusual problem.
>>>
>>> One of our clients uses a program to request map data from one of our
>>> servers. We have a reverse proxy squid cache in front of it. Client
>>> hits squid, which gets data from web server and serves it back to
>>> client.
>>>
>>> Here's the problem. Client uses broken code that times out before
>>> the map data is finished processing. It then resubmits the request.
>>> It'll do this about 10 times before finally dying. Each new request,
>>> however, also times out so nothing is done and lots of time is wasted
>>> (as single one of these requests might take 5 minutes to return).
>>>
>>> So, I've proposed that we use url_rewrite_program to pass the request
>>> to a program which makes the request to the webserver (and DOESN'T
>>> timeout!), it then returns the same URL but by this time the object
>>> is in the cache and the original squid process returns the data from
>>> the cache.
>>>
>>> Is this craziness? Anyone do anything like this before? Or is there
>>> some better, easier way to handle this?
>>
>> There are a couple of things worth trying:
>>
>> * quick_abort_min/quick_abort_max. Make sure they are set to allow
>> squid to finish the first request even after client is gone. This will
>> at least let the retries have shorted generation times.
>>
>> * If you are using Squid-2 collapsed_forwarding is your very best
>> friend. Cupled wit the above it will ensure only the first request
>> gets to the backend and later ones get served whatever data it came up
>> with.
>>
>>
>> * Personally I'd also stick a 5-10 minute minimum cache time on all
>> results if the backend takes 5 minutes to generate.
>>
>> Short caching times still lets you update relatively quickly, but you
>> want to have them stick around just long enough to catch followups and
>> if all clients suddenly got this terrible software they won't kill
>> your service with retries.
>>
>> Amos

-- 
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