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From Miles Libbey <>
Subject Re: unexpected high amount of Cold lookups
Date Mon, 11 Dec 2017 00:01:09 GMT
On Sun, Dec 10, 2017 at 8:56 AM, ezko <> wrote:
> Hi,
> i'm getting a pretty high number of
> proxy.process.http.transaction_counts.miss_cold which I don't expect.
> All my cached objects are set with an explicit Cache-Control max-age , so
> when they expire , if a new copy is retrieved from the origin , it has to be
> new.
> How can i debug this issue ?

Some questions I would be asking myself:
- Is my cache big enough to support my working set size?
proxy.process.cache.wrap_count tells you how often the cache has
wrapped since the last restart.
- When I look at the requested urls and their cache status, Do I get
any hints as to why there are misses? (For instance, perhaps there are
random query strings in the requests making ATS think they are novel
- Do my objects Vary on reasonable headers (eg, *not* user-agent,
cookie, ...)? Perhaps there are too many variants?
- Are there POSTs or other http verbs that would invalidate the cached object?


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