Race condition when using slapo-unique?

[Magne Land <Magne.Land@citrix.com>]

Hi,
I am using OpenLDAP 2.3.43 with BDB 4.5.20 and recently encountered a
problem where two different entries were created with the same mail
attribute value.
The problem is that the mail attribute was defined as unique in slapd.conf:
index mail eq,sub
overlay unique
unique_attributes mail

The two similar entries were created about 300 milliseconds apart. To add to
the confusion, an ldapsearch for the same mail value occurred at roughly
the same time.

So far I have not been able to reproduce this, which indicates that it is a
race condition.

I hope someone can help me, or direct me to some documentation.

Regards,
Magne Land