slow search speed in samba

[Dmitry Chernyak <cdl@inkasbank.ru>]

Hello!

I have a directory with about 500 entries with objectClass'es 
person,(posix/shaadow/samba)Account (i.e., 500 users) and about 100 
entries of other objectClasses.

When I run ldapsearch with filter

(&(uid=*)(objectClass=sambaAccount))

and search one attribute (say, cn), it takes about 8-12 seconds to 
complete. In general, all search filters takes the similar time, 
depending number of returned entries. When I retrieve all attributes 
(about 25 lines) it takes about 1.5 - 2 minutes.

Unfortunatenly, mentioned search filter is that, which samba 3.x runs 
for retrieving accounts list for rigths assignment (say, in trusted 
server mode for Win2k domain). The complete list becames retrieved after 
many minutes of waiting and a number of retries...

I have pres,eq indexes on objectClass & uid.
I tested that with  slapd 2.1.26-1/bdb and slapd 2.0.27-4/ldbm backend 
on Debian Woody and there was not drammatic difference in speed.

Can anybody tell me is such speed normal? How can I improve performance?
Maybe there is some "advanced" in-memory caching technology?

Dmitry Chernyak.