Re: 01/01: nginx: berlin: Disable narinfo caching altogether.

[Mark H Weaver <mhw@netris.org>]

Hi Ludovic,

ludo@gnu.org (Ludovic Courtès) writes:

> Mark H Weaver <mhw@netris.org> skribis:
>
>> ludo@gnu.org (Ludovic Courtès) writes:
>>
>>> civodul pushed a commit to branch master
>>> in repository maintenance.
>>>
>>> commit 8379ba4119e51151d93589a6ef57cb159d94e9f2
>>> Author: Ludovic Courtès <ludo@gnu.org>
>>> Date:   Thu Jun 21 11:41:06 2018 +0200
>>>
>>>     nginx: berlin: Disable narinfo caching altogether.
>>>     
>>>     This is a followup to ebbe4c7f402b6d9cf9c6c2ecf120f49697ab2c49.
>>>     
>>>     * hydra/nginx/berlin-locations.conf (.narinfo): Disable caching.
>>>     * hydra/nginx/berlin.conf: Remove 'proxy_cache_path' directive
>>>     for narinfos.
>>
>> What's the rationale for this change?
>
> From commit ebbe4c7f402b6d9cf9c6c2ecf120f49697ab2c49:
>
>     Somehow nginx appeared to be caching narinfos for longer than needed,
>     which defeated the atime-based cache eviction strategy of 'guix
>     publish'.
>
> In this case, I noticed on berlin that nginx was caching 404s for
> narinfos longer than expected, for reasons I could not elucidate.  Plus
> there’s this atime story.

Although you didn't mention it here, I now remember one reason why it's
a problem for narinfos to be in the cache longer than expected: because
if a narinfo is available but the corresponding NAR isn't, it causes
problems on the client side.  If that's still the case, then it
certainly justifies this change.

      Thanks,
        Mark