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From "Patrick O'Brien" <patrickobr...@tetrisblocks.net>
Subject Re: child always re-validates object fetched from parent
Date Mon, 08 Jan 2018 17:31:11 GMT
Good catch!

This didn't fix the issue by itself, but it did remind me that
proxy.config.http.cache.when_to_revalidate was set to 2 (Always
Stale).

I guess on our non-chained proxies everything worked because of our
rules in cache.config?

I appreciate the advice, Jeremy. Thank you!

On Mon, Jan 8, 2018 at 8:29 AM, Jeremy Payne <jp557198@gmail.com> wrote:
> Can you modify the below to reflect non-zero values ?
>
> ##############################################################################
> # Heuristic cache expiration. Docs:
> # https://docs.trafficserver.apache.org/records.config#heuristic-expiration
> ##############################################################################
> # Setting all of these to zero in order for everything to be considered stale
> # by ATS. If we want to change this in the future, this is where to do it.
> CONFIG proxy.config.http.cache.heuristic_min_lifetime INT 0
> CONFIG proxy.config.http.cache.heuristic_max_lifetime INT 0
> CONFIG proxy.config.http.cache.heuristic_lm_factor FLOAT 0.000000
> ##############################################################################
>
> On Mon, Jan 8, 2018 at 10:24 AM, Patrick O'Brien
> <patrickobrien@tetrisblocks.net> wrote:
>> Hey Jeremy,
>>
>> Here's the full config from the child node:
>> https://gist.github.com/poblahblahblah/a1abdad3d64ebdfba003c75e50c9fe00
>>
>> Thanks for looking!
>>
>> On Sun, Jan 7, 2018 at 8:13 PM, Jeremy Payne <jp557198@gmail.com> wrote:
>>> Can you post the complete records.config from your child cache ?
>>> If I had to guess, it looks like heurstics or fuzzytimer may be set too low ???
>>> But if you provide  a company sanitized version of your records.config
>>> that should give us a better understanding of your setup.
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Wed, Jan 3, 2018 at 6:10 PM, Patrick O'Brien
>>> <patrickobrien@tetrisblocks.net> wrote:
>>>> Hello,
>>>>
>>>> I am testing out hierarchical caching in ATS 7.1.1. Everything seems
>>>> to work, although it looks like the child node is always needing to
>>>> revalidate objects fetched from the parent node. Here are the headers
>>>> on an example GET:
>>>> https://gist.github.com/poblahblahblah/928aaa88c24ef3c05366433a514f1a28
>>>>
>>>> The parent has the object stored in RAM and doesn't require
>>>> validation, but the child thinks the response is stale. Here is the
>>>> cache.config file on both the parent and the child:
>>>> https://gist.github.com/poblahblahblah/36b54ac8b7d75071c1342da6694d3c51
>>>>
>>>> The problem with this is that the connection between the child and
>>>> parent is pretty flaky and when the parent is down we are met with a
>>>> 502: https://gist.github.com/poblahblahblah/d50657354c815040faae50539fa45836
>>>>
>>>> Here is the parent.config on the child:
>>>> https://gist.github.com/poblahblahblah/9f1dcb4cf674c21c80a27173bd0ef81b
>>>>
>>>> Relevant configs from records.config for the parent:
>>>> https://gist.github.com/poblahblahblah/e6ac573e9f9cd63088c2e06e6544d801
>>>> Relevant configs from records.config for the child:
>>>> https://gist.github.com/poblahblahblah/5a6dc02a88b24cafca0e8c70d353b92e
>>>>
>>>> Any guidance on this would be much appreciated.
>>>>
>>>> -patrick

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