Oracle - 合并到n行后提交

Question

我知道如何在n行之后提交一个简单的 UPDATE 语句。

如何使用 MERGE INTO 语句实现它，比如说每10000行后提交：

MERGE INTO incident a
USING 
(
select b.incident_sk incident_sk_bkp , b.mapping_id mapping_id_bkp 
from incident a
join  incident_bkp b
on a.incident_sk=b.incident_sk
where 1=1
and a.mapping_id <> b.mapping_id_bkp
) b ON (a.mapping_id = b.mapping_id_bkp)
WHEN MATCHED THEN UPDATE 
    SET a.mapping_id = b.mapping_id_bkp;

补充问题：对于某些体面硬件上的1,200万条记录是否必要？