tdb transaction nesting and ctdb

[simo]

On Mon, 2009-06-15 at 17:12 +0200, Volker Lendecke wrote:
> On Mon, Jun 15, 2009 at 10:56:04AM -0400, simo wrote:
> > On Mon, 2009-06-15 at 14:59 +1000, tridge at samba.org wrote:
> > > > Did you get Tridge's opinion on this? Is this going into the
> > >  > main Samba tdb code any time soon?
> > > 
> > > I think it's a good idea, we just need to make sure we set the "allow
> > > nesting" flag on all the existing users that need it.
> > 
> > I am a bit unclear in what circumstances nesting transactions (as
> > implemented) is useful ?
> 
> It's useful when initializing the s3 registry.tdb on a busy
> server. This takes *ages* because we have so many fsync
> calls. The enclosing transaction makes this a single set of
> fsync/msync calls which is a lot faster.

But it is also dangerous, is speed more important in this case?
I know it's a situation where we are between a rock and a hard place :-/

Simo.

-- 
Simo Sorce
Samba Team GPL Compliance Officer <simo at samba.org>
Principal Software Engineer at Red Hat, Inc. <simo at redhat.com>