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

[ludo@gnu.org (Ludovic Courtès)]

Hello,

Mark H Weaver <mhw@netris.org> skribis:

> 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.

Yes, that too.

We’ll see how it goes and if it performs badly let’s revert or adjust.

Ludo’.