[SSSD] No negative cache with sssd_nss

Simo Sorce simo at redhat.com
Tue Jul 3 02:13:12 UTC 2012


On Tue, 2012-07-03 at 04:02 +0200, Jan Engelhardt wrote:
> On Tuesday 2012-07-03 03:44, Simo Sorce wrote:
> >
> >The memory cache does not do negative caching indeed, but sssd_nss does,
> >however it caches negative entries for a very short period of time.
> 
> How short is the default?
> 
> >However in order to notice this you'd need to have a huge amounts of
> >unexisting entries you query in sequence.
> 
> It's a very bounded set of user/groups (< 5).
> 
> >> On the whole picture, I am trying out "bindfs", and how long it takes to 
> >> extract e.g. a kernel tarball with a given, but fixed over all test 
> >> runs, set of bindfs options. It's mostly about repeated getpw*/getgr* 
> >> lookups (at least one per created file).
> >
> >Ah I see, you are paying the penalty for a full roundtrip to sssd_nss
> >for each file created. I think we can work on adding some negative
> >caching to the memory cache so to reduce from one call every file to one
> >call every 5 seconds or so.
> >
> >Would you mind opening a ticket for it ?
> 
> The default trac interface is horrible. There just is no link on the
> frontpage to submit an issue. (Compare with sourceforge project pages
> where there is clearly "support"/"tracker". Or people accept stuff on
> mailing lists.)

When you are logged in there is a "New Ticket" button ...

Don't worry I'll open it.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York




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