slow startup after upgrade

Corinna Vinschen corinna-cygwin@cygwin.com
Wed Feb 18 13:06:00 GMT 2015


Hi Roger,

On Feb 18 11:26, Roger Orr wrote:
> Hello Corinna,
> 
> I've just been trying out both the 2015-02-18 10:30:19/44 UTC and
> 2015-02-17 21:27:23/48 UTC patches.
> 
> Both are now down to the same timings as with a 'files' entry in
> /etc/nsswitch.cfg, (and there's no detectable speed difference between
> them.)
> 
> The scope restriction in the second query to \System reduces the query
> time to 1.1 - 1.3 ms (was 4 seconds)

Wow!  That's what I had hoped for but it's really incredible to read that.

> and also it no longer opens 14
> TCP/IP sessions to various ldap servers around the planet (!)

Uh, that might be the result of the other changes which don't open an
LDAP connection to fetch group info.  14 connections probably means,
you're in 14 groups in other domains than your login domain.

> I note that mkpasswd and mkgroup do still open many sessions to the
> ldap servers, but that may be inevitable.

Cygwin is using a bulk LDAP request, fetching 100 entries in each call.
I'm not quite sure how all that works under the LDAP library hood, but
one one hand mkpasswd/mkgroup need to make a lot of requests if you
enumerate your entire organization, and every domain needs its own
connection.

> It's not an issue directly,
> of course, since I'll no longer need to make use of these, but it
> perhaps might indicate another place where the ldap queries are
> sub-optimal.

The enumeration queries got the same treatment, so I assume this is
really just a result of having to enumerate all the domains.

> Thanks for your rapid response on this issue!

Same to you!  I'm glad to get testers in such big environments since, as
I said, it's kinda hard to test big stuff in a tiny domain like mine at
home :}

Final question:  Given the above improvement, are you going to run in
"db" only setting for the time being?  That would make some good long
time test... :)


Thanks a bunch,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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