Re: [squid-users] external_acl children...

John Doe wrote:
>> 2008/08/19 17:54:35| WARNING: All filter processes are busy.
>> 2008/08/19 17:54:35| WARNING: up to 1 pending requests queued
>> 2008/08/19 17:54:35| aclMatchExternal: 'filter' queue overload. Request
>> rejected '/path/to/image2.gif'.
>> ...
>
> quick question: does that mean I need as many children as the max number of 'requests/s' (at a given time)...?
> By exampe, if I have up to 100 concurrent requests, do I need 100 children to prevent rejected requests?
> It says "1 pending requests queued", and immediatly after, "queue overload".
> What is the queue capacity?
> In my test, I only had 5 images...
>

Sort of, you need one helper 'slot' for each concurrent request.

You can increase the number of 'slots' available by increasing the
number of children/helpers and the number of concurrency=N each can handle.

at concurrency=1 you need 100 children for 100 requests,
at concurrency=2 you need 50 children for 100 requests
etc.

This is mitigated further by caching the helper results for TTL=N time.
But worst-case is still 1 slot per request until the ACL result
mini-cache finds a duplicate.

Amos

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