dynlist performance

["POISSON Frédéric" <frederic.poisson@admin.gmessaging.net>]

Hello,

I'm testing the dynlist overlay on OpenLDAP 2.4.38 because i have a static group of around 10K uniqueMember. I want to have now a equivalent group with dynlist. 

I have configured my overlay dynlist like this :
dn: olcOverlay={2}dynlist,olcDatabase={1}bdb,cn=config
objectClass: olcOverlayConfig
objectClass: olcDynamicList
olcOverlay: {2}dynlist
olcDlAttrSet: {0}groupOfURLs memberURL uniqueMember

And my group is quite like OpenLDAP example in documentation :

dn: cn=GeneralisationDyn,ou=Groups,dc=example,dc=com
objectClass: top
objectClass: groupOfURLs
cn: GeneralisationDyn
memberURL: ldap:///ou=People,dc=example,dc=com??one?(objectClass=person)
uniqueMember: uid=user1,ou=People,dc=example,dc=com
uniqueMember: uid=user2,ou=People,dc=example,dc=com
[...]

My backend is Berkeley DB and i have tune it in order to have quite fast responses on searches, and locally on my server (virtualized with a single proc), it take that time to return the entries found by memberURL :

real    0m0.272s
user    0m0.040s
sys     0m0.023s

If i run an ldapsearch to see all uniqueMember of my dynamic group it take around 8 to 10 seconds to have the output !

Why a so big difference of response time in a search of entries and a search of uniqueMember inside a dynamic group ?
Is there some tuning for dynlist plugin ? 

Notice also that when i search uniqueMember inside my static group  with quite same number of uniqueMember) i have less than 0.1 seconds of real time.


Thanks, 
Regards,
--

Frederic Poisson