The following MERGE request logs all error types, including data errors, referential integrity errors, and USI errors, with an error limit of 100 errors.
MERGE INTO tgttbl AS t1 USING (SELECT c1,c2,c3 FROM srctbl) AS t2 ON t1.c1=t2.c1 WHEN MATCHED THEN UPDATE SET t1.c2=t2.c2 + t1.c2, t1.c3=t2.c3 WHEN NOT MATCHED THEN INSERT INTO t1 VALUES (t2.c1, t2.c2, t2.c3) LOGGING ERRORS WITH LIMIT OF 100;