你这个表述有点绕。
我可以理解为，有的表cdc到下游是update，有的表cdc到下游是delete+update。
出现delete+update的表，直接update也是可以的，你是这个意思吗？
https://github.com/pingcap/tiflow/issues/9086
我觉得你可以看看这个。
Avro and CSV Protocol, does not emit the old value for the update event to downstream, so if the primary key is updated, the old data cannot be deleted from the downstream data system.
By split the update event into delete event and insert event, the old data can be delete first, and then insert the new data.
看上去像是为了兼容某些协议而作出的增强。
我得承认我对ticdc并不熟悉。这算是一种可能性。