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Re: Performance degredation between 2.4.39 and 2.4.44

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/