f0:string f1:int f2:int f3:double (all can be null)
primary key: f0,f1,f2
partition key: f1
bucket key: f2
bucket count: 2
add deletion vector

Msgs:
snapshot-1-2
Add: Two roads diverged in a wood, and I took the one less traveled by, And that has made all the difference., 10, 1, 11.0
Add: Alice, 10, 1, 11.1

Add: Bob, 10, 0, 12.1
Add: Emily, 10, 0, 13.1
Add: Tony, 10, 0, 14.1
Add: Alex, 10, 0, 16.1
Add: David, 10, 0, 17.1

Add: Lucy, 20, 1, 14.1
Add: Paul, 20, 1, 18.1

snapshot 3-4
Delete: Tony, 10, 0, 14.1
UpdateAfter: Alice, 10, 1, 19.1

commit_messages-01: partition 10, bucket 1, snapshot 3-4
data_split-01-03: snapshot-4
