When a transaction prevents sql apply service, it can be found by querying DBA_LOGSTDBY_EVENTS view.
select * from DBA_LOGSTDBY_EVENTS order by EVENT_TIMESTAMP, COMMIT_SCN;
Using this query, transaction identification information is listed.
XIDUSN NUMBER (Transaction ID undo segment number)
XIDSLT NUMBER (Transaction ID slot number)
XIDSQN NUMBER (Transaction ID sequence number)
To skip the transaction DBMS_LOGSTDBY.SKIP_TRANSACTION procedure is used.
First, LOGICAL STANDBY APPLY must be stopped.
ALTER DATABASE STOP LOGICAL STANDBY APPLY;
Then, transaction is skipped.
EXECUTE DBMS_LOGSTDBY.SKIP_TRANSACTION(XIDUSN, XIDSLT, XIDSQN);
Last, LOGICAL STANDBY APPLY is started.
ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE;
To find which transaction being skipped.
select * from DBA_LOGSTDBY_SKIP_TRANSACTION;