In order to test incremental reflection refreshes we have set up the following test case:
Created a static table with "Identify new records using the field: modified_date. The physical data source is an Oracle table with 12486 rows. I created the initial raw reflection and then executed a select count(*) query and the result was as expected 12486 rows.
I then performed a manual refresh of the reflection without having made any changes to the physical data source. The select count(*) query returned 12758 rows 272 rows have been duplicated in the reflection.
I again performed a manual refresh and now the reflection contains 13030 rows - with 544 duplicate rows.
My understanding was that if the underlying data source has not changed, the reflections should not change.
Am I misunderstanding the the functionality of the incremental update?