f0:string f1:int f2:int f3:double (all can be null)
partition key: f1
bucket key: f2
bucket count: 2

Msgs:
snapshot-1
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: Lucy, 20, 1, 14.1
NoCompact


data_split-01
with snapshot-1, partition-10, bucket-1

commit_messages-01
with snapshot-1
