Data Replication requires Oracle to be running in ARCHIVELOG mode.
By default, ARCHIVELOG mode is not enabled. To enable ARCHIVELOG mode, issue the following statements:
SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
ALTER DATABASE ARCHIVELOG;
ALTER DATABASE OPEN;
SHUTDOWN IMMEDIATE;
STARTUP;
If you use the Oracle init.ora initialization parameter file, you must edit the appropriate parameters in this file to identify the archive log target and file name format. If you use a server parameter file (spfile), you must execute some ALTER SYSTEM SET SQL. For more information, see the Oracle Administrator Guide.