Re: openldap.git branch master updated. 2d5996ac603391ddbd618425f88eb13e5e0e2cc0

[Howard Chu <hyc@symas.com>]

Michael Ströder wrote:
> Howard Chu wrote:
> > A note about this revised patch - accesslog uses op->o_time/op->o_tincr to
> > generate its RDNs. We actually have a problem here in that microsecond
> > resolution may no longer be adequate. Back in January I was on site with a
> > customer whose 64-core server was hitting ~1 million queries/sec. Granted,
> > that was with syslog and accesslog disabled; with logging enabled we're far
> > more limited.
> >
> > Very soon we're going to need higher resolution when logging is enabled.
>
> At that speed I'm mostly concerned about entryCSN values and MMR conflict
> resolution.

Note that CSNs already support finer than microsecond resolution.
But since delta-syncrepl relies on accesslog, that's more of a concern.

As for syslog - currently, with my experimental syslog() code, my best result 
still takes 60% longer when running with -s256 (STATS loglevel) vs -s0. If I 
comment out the send() on the /dev/log socket to rsyslogd, and leave all the 
message formatting code intact, it's only 10% slower. So most of the slowdown 
is in the actual send() syscall.

(Using the original code is around 2.5x slower for -s256 than -s0)

--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/