When upgrading from Liferay 6.1 GA2 to 6.2 SP10 using Oracle 11.2 DB, there are various WARN messages that are displayed as a result of the attempt to create a unique index:
19:51:33,591 WARN [localhost-startStop-1][BaseDB:106] ORA-01452: cannot CREATE
UNIQUE INDEX; duplicate keys found_: create unique index IX_3A200B7B on MBThread
(uuid_, groupId); [Sanitized]
With the understanding that certain indexes were made non-unique based on
LPS-21590 and then re-added in LPS-31465, we should still address the issue by handling the unique index violation during verification to be configurable. Some potential configuration values would be to print a more informative warning (the result of a group by having query), remove all but the smallest primary key, or remove all but the fist one returned by the DB.