Major Description
For table test with two column a(primary key), b.
If I do following operations in client side:
- openTable(test) to get a kudu table object KuduTable1 whose schema is (a, b)
- Add a column c to table test.
- openTable(test) to get another kudu table object KuduTable2 whose schema is (a, b, c)
- Insert 1 row ("d", "e", "f") using KuduTable2
- Upsert 1 row ("d", "g") using KuduTable1
The expected result is ("d", "g", "f") since I hope to keep the value of column c.
But the result i got was ("d", "g", NULL)
After looking through the code, I think the original reason is that the isset_bitmap is not all 0 at start.
So I initialize the bitmap like below: 
After this modification, the result is as my expect.
So I wonder if it is a bug since normally a user does not want to change the column which he did not request to.
