Charles, Mark and Erich Thank you for your help. Charles, thanks for the reference to the 139666.1 note. My case is close to the case 3, but not exactly because I build a unique index (and in the Note the index built as a nonunique which makes a difference according to Mark's Email). so I have opened a SR with Oracle and will hope to get some definite answer from them. Erich, my case seems to contradict the info you have found in the admin guide. So may be I have done something incorrectly . I'll post whatever answer I will get from oracle thank you Gene Gurevich -- //www.freelists.org/webpage/oracle-l