Dual bind, single unbind?

[Bjørn Ruberg <bjorn@ruberg.no>]

Hi everyone,

I am currently writing a Munin [1] [2] plugin for OpenLDAP, using the 
slapd-monitor backend. To be able to interpret and properly visualize 
the statistics collected, I need to better understand some aspects of 
how slapd works (and as such, this is probably not my last post to the 
list :)

Among the parameters that are graphed are the "cn=operations, 
dc=monitor" branch. Here, the "bind" and "unbind" operations are 
counted. However, I find that quite a few more binds than unbinds take 
place. The log shows me the following, for most binds/unbinds (the log 
extract is trimmed for readability):

slapd[28594]: op=0 BIND dn="cn=adm,dc=acme,dc=com" method=128
slapd[28594]: op=0 BIND dn="cn=adm,dc=acme,dc=com" mech=SIMPLE ssf=0
slapd[28594]: op=2 UNBIND

To me it seems like the bind operation is registered twice, which (from 
a "how many binds has been performed" state of view) somewhat confuses 
the statistics.

How should this be interpreted? What really happens and what is the 
reason for these "double binds"?

Thank you,

--
Bjørn

[1] http://www.linpro.no/projects/munin/ (old web site)
[2] http://munin.projects.linpro.no/ (new web site)