OpenDJ vlv index error: # Server-side sort failed: Unwilling to Perform

Question

I'm using OpenDJ 3.0.0 release version.

I have two base dns, 1st is dc=tenant1, 2nd is dc=tenant2, the vlv index I created is based on dc=tenant1, but the ldap search happened on dc=tenant2

Here is the vlv index, which looks like filter: (&(objectClass=ns-nationsky-base-subject)(uid=)(cn=))

base dn: dc=tenant1 sort order:uid cn mail scope: one level

There will be "# Server-side sort failed: Unwilling to Perform" when I try to use ldapsearch with a vlv control, like below:

/ldapsearch -p 1389 -h localhost -D 'cn=Directory Manager' -w 'password' -b 'ou=People,ou=Subjects,dc=tenant2' -G 0:2000:1:0 -s one --sortorder uid "(uid=a)" cn

It all works good but it will always be an error of "# Server-side sort failed: Unwilling to Perform" if there are too many entries in my server.(say 15000)

from the access log , I can see unindexed search [19/Sep/2016:23:06:38 +0800] SEARCH REQ conn=35 op=1 msgID=2 base="ou=People,ou=Subjects,dc=tenant2" scope=one filter="(uid=a)" attrs="cn" [19/Sep/2016:23:06:40 +0800] SEARCH RES conn=35 op=1 msgID=2 result=0 nentries=8458 unindexed etime=2543

Any idea how I can fix it ?

Answer 1

A VLV Index and queries are really meant to browse a well know set of entries (like all users) and not varying sets of entries.

So, in order to use a VLV Index, the search request must match the base, the scope, the filter and the sorting order defined for that index (and filters should be constant).

If the VLV index was defined with (&(objectClass=ns-nationsky-base-subject)(uid=)(cn=)), then a search with (uid=a) will not match the index and thus cannot be used.

Server side sorting is a very expensive request, this is why, when there is no index, the server will refuse to sort many entries (governed by index-entry-limit). While it is possible to increase this limit, this has very serious implications in the amount of resources that are used in the server and may seriously impact performances of the server.