Delivery Tx and Half Tx

File system: fsync


Delivery transaction (ordinary two phase commit)

f1---> f1.t--->f1.p--->f1

(1) Begin delivery transaction f1-->f1.t
(2) write data to f1.t
(3) run fsync, f1.t --> f1.p
(4) commit tx, f1.p --> f1

Half transaction to ensure the series of operations commited once only
There is no abort but carried forward. They are idempotent operation

fsync issued by client and client receive ack for the commit then
the half transaction is completed