ORA-56942
Read-only tables or tablespaces prevented Daylight Saving Time upgrade
Cause
An attempt was made to start a DST upgrade window when there were tables with TIMESTAMP WITH TIME ZONE data that were in read-only mode or stored in read-only tablespaces.
Action
Alter read-only tables with TIMESTAMP WITH TIME ZONE data to allow write operations or alter read-only tablespaces to allow write operations.