Oracle Error : ORA-19905: log_archive_format must contain %%s, %%t and %%r

Cause: log_archive_format is missing a mandatory format element. Starting with Oracle 10i, archived log file names must contain each of the elements %s(sequence), %t(thread), and %r(resetlogs id) to ensure that all archived log file names are unique.

Action: Add the missing format elements to log_archive_format.