Syncrepl fails with LDAP_RES_INTERMEDIATE - SYNC_ID_SET

[Serge Dubrouski <sergeyfd@gmail.com>]

Hello -

I've had provider-consumer configuration working all right for about a
month. Today  I had to upgrade OS (RedHat 5) and restart services.
After that one of my consumers failed with the following errors:

Jan 24 19:32:54 rome slapd[2236]: do_syncrep2: rid=012
LDAP_RES_INTERMEDIATE - SYNC_ID_SET
Jan 24 19:33:05 rome last message repeated 11 times

And then started to delete records:

Jan 24 19:33:40 rome slapd[2236]: syncrepl_entry: rid=012 be_modify (0)
Jan 24 19:33:40 rome slapd[2236]: do_syncrep2: rid=012 LDAP_RES_SEARCH_RESULT
Jan 24 19:33:40 rome slapd[2236]: do_syncrep2:
cookie=rid=012,csn=20090125022613.018210Z#000000#000#000000
Jan 24 19:33:40 rome slapd[2236]: nonpresent_callback: rid=012
nonpresent UUID e7d215a2-3cc4-102d-8ea2-9f51782b1a5b, dn c=GB
Jan 24 19:33:40 rome slapd[2236]: nonpresent_callback: rid=012
nonpresent UUID e7f0d37a-3cc4-102d-8ea3-9f51782b1a5b, dn o=....
Jan 24 19:33:40 rome slapd[2236]: nonpresent_callback: rid=012
nonpresent UUID e7f61ed4-3cc4-102d-8ea4-9f51782b1a5b, dn .....

To fix the problem I had to copy  database from the provider to
consumer and then restart that consumer.
So what does that error mean and how to avoid it in the future?

OpenLdap 2.4.13
DB 4.6-21

Thanks.

-- 
Serge Dubrouski.