[PATCH] Use idmap cache for all pdb backends.

Volker Lendecke Volker.Lendecke at SerNet.DE
Fri May 2 12:51:02 MDT 2014

On Fri, May 02, 2014 at 08:47:53PM +0200, Volker Lendecke wrote:
> On Sat, May 03, 2014 at 06:26:46AM +1200, Andrew Bartlett wrote:
> > Sorry to be a pin, but not all callers go via the pdb_ functions.  The
> > Python passdb API (for example) does not, it calls the backends directly
> > via the methods pointers.
> > 
> > Also, can you explain a bit more why we should cache for the
> > pdb_smbpasswd and pdb_tdbsam modules?  Caches naturally bring up issues
> > of cache coherency, and we should only use them when looking up the
> > result has a significant cost.  You imply that some situation using
> > other than pdb_ldapsam calls LDAP, can you provide some more detail on
> > that?
> Performance. smbpasswd needs to scan a potentially large
> file. And both smbpasswd and tdbsam need to traverse the
> group_mapping.tdb for gid2sid calls, which can also be
> large.

Ah, and remember, we are doing this on every single file
open when reading an acl. If the acl is large, many times
per acl. So for even mildly metadata heavy workload this
really counts.


SerNet GmbH, Bahnhofsallee 1b, 37081 Göttingen
phone: +49-551-370000-0, fax: +49-551-370000-9
AG Göttingen, HRB 2816, GF: Dr. Johannes Loxen
http://www.sernet.de, mailto:kontakt at sernet.de

More information about the samba-technical mailing list