MERGE statement and APPEND hint Options

[Starikovsky]

From the functional point of view it is clear to me how the MERGE statement works.
It is also clear to me APPEND hint will allocate space beyond HWM each time an INSERT statement is issued.

> What I'm Wondering Is
How does MERGE statement works with an APPEND hint?

> Scenario
Assume a large partitioned table populated/updated from a staging area via MERGE statement.
MERGE statement will UPDATE when PK match and will INSERT when PK doesn't match.
Assuming insertable and updateable rows are scatered in staging area MERGE will issue either INSERT or UPDATE statements as needed.

> Question
If this is the case, it's safe to say MERGE/Insert will push HWM a little higher each time a new row is inserted? If it works this way process will be allocating a lot of space and leaving huge amounts of unused space under the HWM, is that correct?


Thank you in advance.