Oracle Solution for Error ora-23402

ORA-23402: refresh was aborted because of conflicts caused by deferred txns

What triggered the Error:

ere are outstanding conflicts logged in the DefError table at the materialized view's master.

What should we do to fix it:

solve the conflicts in the master DefError table and refresh again after the table is empty. Alternatively, refresh with refresh_after_errors set to TRUE, which will proceed with the refresh even if there are conflicts in the master's DefError table. Proceeding despite conflicts can result with an updatable materialized view's changes appearing to be temporarily lost (until a refresh succeeds after the conflicts are resolved).