| ERROR | no public threads are available for mounting |
| CAUSE | The INIT.ORA parameter thread is zero, its default value. There are no threads which have been publicly enabled, and not mounted. |
| ACTION | Shutdown the instance, change the INIT.ORA parameter to a thread which is privately enabled and not mounted. If the database is open in another instance, then a thread may be publicly enabled. |
| 719849 | ORA-01620 during Oracle upgrade to version 9i |