Re: Testers needed: New passwd/group handling in Cygwin

[Achim Gratz <Stromeko@nexgo.de>]

Corinna Vinschen writes:
> The stuff in the `id' application is not cached at all.  Caching is
> inherited from the parent process, but the parent never asked for all
> your groups so it hasn't cached this information.  Every invocation of
> id has to request the group info anew.

OK, then I was misunderstanding what caching meant.  I was operating
under the assumption that there'd be something like a session cache that
serves all Cygwin processes in the same process tree.

> Do you have a very slow connection to your DC by any chance?  I admit
> that I never tested with 440 groups, only with about 30 or so, but 13
> seconds sounds *very* lame.

That's around 33 lookups per second; not great, but also not bad (I'm
far from the only user of that DC obviously).  I'll have to check what
our web application server is doing (albeit it uses a connection pool to
amortize the connection overhead), but I don't think it'll do much more
than about 200 peak.  The answers can be insanely large depending on
what and how you ask, too.  In any case, based on the fact that I'm
certainly not in as many groups as some other folks, I don't think I can
drop file-based operation at the moment (which I really hoped I could).

> OTOH, this isn't *quite* unexpected.  Right now, the LDAP connection to
> the DC is opened and closed for every single account request.  I wasn't
> sure yet if the ldap connection should be opened only once per process
> and then stay open for the rest of the process lifetime.  This sounds so
> much like wasting sockets...

See above, there's a timeout on each pooled connection, again I'll have
to ask how long it is (I think somewhere in the single digits seconds
range, we don't want to tie up the DC for too long).

> The fact that the shells are doing it right seems to indicate that this
> isn't a generic problem.  I can't debug this, though.  Can you see if
> you can figure out what's going on under the hood?  Does strace show
> anything of interest?  Can we perhaps set up some joint debugging via
> private mail during the next couple of days?

I can't dig further into this for the next two weeks.  I need to get
some work done, so I have rolled the snapshot back for now.  I'll get
back to you when this is out of the way, thanks for the offer.


Regards,
Achim.
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