Re: Performance degredation between 2.4.39 and 2.4.44

[Howard Chu <hyc@symas.com>]

Quanah Gibson-Mount wrote:
> --On Monday, February 29, 2016 2:20 PM -0800 Quanah Gibson-Mount
> <quanah@zimbra.com> wrote:
>
> > --On Monday, February 29, 2016 2:11 PM -0800 Quanah Gibson-Mount
> > <quanah@zimbra.com> wrote:
> >
> > > I've noticed a bit of a performance degradation between the 2.4.39
> > > release and 2.4.44, when doing searches that require ACL processing
> > > (anonymous or authenticated user).
> >
> > That should be, when doing searches, period. ;)
>
> This was introduced in 2.4.44 with the fixes for ITS8266.  The new
> olcDbRtxnSize attribute defaults to 10000.  However, the more extreme the
> ratio between the batch size and the db size, the more perf is significantly
> impacted.  Dropping down to an approximate 300,000 DB, we see the following.
>
> 0: 9.145s, 9.450s, 9.272s, 9.129s (no batch size)
> 100: 1m31.463s, 1m31.850s, 1m30.230s, 1m29.850s (3000:1)
> 1000: 17.910s, 17.778s, 17.784s, 17.556s (300:1)
> 10000: 10.067s, 9.947s, 9.919s, 9.960s (30:1)
> 100000: 9.437s, 9.324s, 9.272s, 9.346s (3:1)
>
> So apparently, you want the ration to be no more than 30:1, otherwise
> perfomance degrades substantially.

On a 1M entry database I see no performance difference between using the 
default rtxnsize (10000) and setting it to zero. Verified using both head and 
RE24.

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