slow search on indexed attribute

[PATRICK H RADTKE <phr2101@columbia.edu>]

I have a group with 5000+ members.

If I run
ldapsearch -h hobo -p 3401 "(&(cn=student)(objectClass=posixGroup))"
attr=cn gidnumber objectclass

I get results in 0.5 seconds.
however when I run

note the gidnumber of group student is 317

ldapsearch -h hobo -p 3401 "(&(gidnumber=317)(objectClass=posixGroup))"
attr=cn gidnumber objectclass

it takes about 90 seconds to return

I ran the server with -d 256
and both queries look the same on the server side (apart from the
cn/gidnumber part of the query, and the fact one takes 90 seconds longer
to return)

from my slapd.conf

#Indices
index default eq
index           objectClass,uidNumber,gidNumber         eq
index           cn,memberUid,uid                        pres,eq

both gidnumber and cn are indexed.

I'm running openldap 2.1.25 on solaris 9.
I'm using ldbm (I know it is old and should switch, but I already have
enough stuff to do)

I've reindexed the db multiple times with slapindex and there has been no
change in performance.


any ideas?


thanks,

Patrick Radtke
Systems Programmer
Columbia University