The issue is that a table with the name schema_owner.table_name exists on the target.
Here in the copy command, the sync process tries to rename target table with the source table name, but if the table name already exists on the target it will not be able to do so.
Here is an example
Config file:
o.source_SID
schema_owner.table_name schema_owner.target_table_name target_host@o.target_SID
With the above configuration, if the target has another table schema_owner.table_name, copy command will not work.
