ORA-00053: maximum number of enqueues exceeded
Cause: Ran out of enqueue state objects.
Action: Increase the value of the ENQUEUES initialization parameter.

ORA-00041: active time limit exceeded – session terminated
Cause: The Resource Manager SWITCH_TIME limit was exceeded.
Action: Reduce the complexity of the update or query, or contact your database administrator for more information.

ORA-00029: session is not a user session
Cause: The session ID specified in an ALTER SYSTEM KILL SESSION command was not a user session (for example, recursive, etc.).
Action: Retry with a user session ID.

ORA-00028: your session has been killed
Cause: A privileged user has killed your session and you are no longer logged on to the database.
Action: Login again if you wish to continue working.

ORA-00027: cannot kill current session
Cause: Attempted to use ALTER SYSTEM KILL SESSION to kill the current session.
Action: None.

ORA-00026: missing or invalid session ID
Cause: Missing or invalid session ID string for ALTER SYSTEM KILL SESSION.
Action: Retry with a valid session ID.

ORA-00024: logins from more than one process not allowed in single-process mode
Cause: Trying to login more than once from different processes for ORACLE started in single-process mode.
Action: Logoff from the other process.

ORA-00221: error on write to control file
Cause: An error occurred when writing to one or more of the control files.
Action: See accompanying messages.

ORA-00217: control file could not be resized for new record types
Cause: The control file was missing some new record types supported by this release. These record types are automatically added by resizing the contol file during mount. The resize has failed.
Action: Look in the alert log for the reason that the resize has failed. If indicated in the alert log, give the control file more space. Otherwise, use the CREATE CONTROLFILE script dumped to the trace file to create a new control file.

ORA-00216: control file could not be resized for migration from 8.0.2
Cause: The control file created by release 8.0.2 was missing some record types. These record types are automatically added by resizing the control file during mount. The resize has failed.
Action: Look in the alert log for the reason that the resize has failed. If indicated in the alert log, give the control file more space. Otherwise, use the CREATE CONTROLFILE script dumped to the trace file to create a new control file.