1.create append main table
pt:int | value:int
partition key: pt

2. main table write
Add: 1, 110

3. main table create branch test

4. main table alter table: "scan.fallback-branch", "test"

5. test branch write
Add: 2, 210

6. main table alter table: add value2 field : int

7. test branch alter table: add value2 field : int

8. main table write
Add: 1, 120, 1200

9. test branch write
Add: 2, 220, 2200

data-split-0-1: main branch fallback batch scan
data-split-pt-0: pt branch batch scan
