Performance of Indexes

we are doing some performance testing on Static Groups...we have created a Static Group with around 20k members. and when we

we have created an group with around 20,000 Members and the file looks like this

dn:cn=salaried group,ou=groups,dc=yyyyy,dc=com

objectlcass:top

objectclass:groupofuniquenames

cn:salaried group

uniquemember: uid=test00001,ou=people,dc=yyyy,dc=com

uniquemember: uid=test00002,ou=people,dc=yyyy,dc=com

.....

....

...

...

..

uniquemember: uid=test20000,ou=people,dc=yyyy,dc=com.

I have imported the above file and then performed the search operation and observed the following results:

1) IF i make a search for "uniquemember=uid=testooo10,ou=people,dc=yyy,dc=com", the search time is around 300ms

2) for the search "uniquemember=test05020,ou=people,dc=yyyyy,dc=com" the searchtime is 800ms

3) for the search "uniquemember=test9999,ou=people,dc=yyyyy,dc=com" the searchtime is 2000ms.

Iam a little bit confused with the way the Indexes operate because,,,,from the results i oberved above....i feel that the values for the uniquemember attribute are stored in the same order as that in the ldif file.... is that how the entry ID for the uniquemember attribtue are created?is there anyway we can know the orded in which the index of an attribtues stores it's values?

[1403 byte] By [anandkaturia] at [2007-11-27 6:45:04]
# 1

Hi

What you are experimenting is not due to the indexes, but with the way DS select entries from the index and then verify that the entry still matches the filter before returing it.

The algorithm used to check filters against an attribute with many values (20K is definitely a lot), combined with the fact that these values are Distinguished Names (ie the DN normalization cost is also high) result in a response time that is linear according to the position of the DN in the array of values.

This can be worked around with the nsslapd-searchtune parameter (and I let you search for the technote about this parameter on this forum).

Alternately, Directory Server 6.0 does contain some major improvements for DNs and Groups, and now scales much better even up to 100,000 members.

Regards,

Ludovic

ludovicpa at 2007-7-12 18:16:42 > top of Java-index,Web & Directory Servers,Directory Servers...
# 2
Thanks for the reply.....I was searching iD;s with sorted ..So the search time was linear as you said....once again thanks for the information
anandkaturia at 2007-7-12 18:16:42 > top of Java-index,Web & Directory Servers,Directory Servers...