Re: [squid-users] How does Squid prevent stampeding during a cache miss?

Squid 2.x supports this:

# TAG: collapsed_forwarding (on|off)
# This option enables multiple requests for the same URI to be
# processed as one request. Normally disabled to avoid increased
# latency on dynamic content, but there can be benefit from enabling
# this in accelerator setups where the web servers are the bottleneck
# and reliable and returns mostly cacheable information.

It's exactly what you're looking for. Basically it causes Squid to
request the URL from the origin server one time, and serves the other
requests the stale content.

On Sat, Jul 31, 2010 at 11:44 AM, Ryan Chan <ryanchan404_at_gmail.com> wrote:
> For example, put Squid as a reverse proxy mode to
> http://www.example.com/heavyduty.php (expire set to 1 hour, need 10s
> to generate).
>
> When the file is just expired, large amount of clients (e.g. 10K)
> request for this file reached the Squid at the same time.
>
> Are there any heuristics performed by Squid to avoid forwarding all
> the 10K requests to the upstream?
>
Received on Sat Jul 31 2010 - 18:15:53 MDT