Abysmally poor write performance

[Jason Tackaberry <tack@auc.ca>]

Hi everyone,

Now I know that LDAP (or, perhaps more accurately, OpenLDAP) is not
tuned for writes, but I'm running into such bad performance that I'm
convinced I must have configured things very wrong, so I'm asking here
for help.

Using RedHat 8's OpenLDAP 2.0.25, I have populated an LDAP directory
with 200 entries.  The total size of all gdbm files is about 1500kb. 
Each user (entry) has 7 objectClasses: top, person,
organizationalPerson, inetOrgPerson, posixAccount, shadowAccount,
qmailUser.  slapd is configured to maintain these indices:

index   objectClass,uid,uidNumber,gidNumber,memberUid   eq
index   cn,mail,surname,givenname,mailAlternateAddress eq,subinitial

The system is a 1GHz P3 with 256M of RAM and SCSI disks (it is a Dell
server).  Updating a single entry with GQ can take up to 5 seconds to
write.  I just now wrote a script to update gidNumber on the 200 entries
using ldapmodify(1), and it took 5 minutes 9 seconds.

Updating a field in 200 records in a table with SQL, for example, would
finish in a fraction of a second.  I'm not expecting that kind of
performance with OpenLDAP, but I think 5 minutes to do the same thing
means something is wrong somewhere.

Any advice?  I hope I've supplied all relevant information.

Thanks,
Jason.

-- 
Jason Tackaberry  ::  tack@auc.ca  :: 705-949-2301 x330 
Academic Computing Support Specialist
Information Technology Services
Algoma University College  ::  www.auc.ca