Good question, the database was completely empty before the installation, I have dropped and created again just before starting "rhqctl install"
The log fragment of psql:
grep -i rhq_storage /var/log/postgresql/postgresql-9.2-main.log
...
2013-11-12 10:33:54 CET ERROR: table "rhq_storage_node" does not exist
2013-11-12 10:33:54 CET STATEMENT: DROP TABLE RHQ_STORAGE_NODE
2013-11-12 10:33:54 CET ERROR: sequence "rhq_storage_node_id_seq" does not exist
2013-11-12 10:33:54 CET STATEMENT: DROP SEQUENCE RHQ_STORAGE_NODE_ID_SEQ
2013-11-12 10:39:41 CET ERROR: duplicate key value violates unique constraint "rhq_storage_node_unique"
...
in those 6 minutes something has happened...
This is the very first "insert into RHQ_STORAGE_NODE ..." statement in the log, and already breaks the uniqueness!
Attila