A control processing device includes a determining unit that determines whether a write of a transaction is to be executed using a write lock or without using the write lock upon receiving a write command of the transaction, a writing unit that acquires the write lock for the transaction and executes the write of the transaction when the determining unit has determined that the write of the transaction is to be executed using the write lock, an optimizing unit that discards the write command of the transaction when the determining unit has determined that the write of the transaction is to be executed without using the write lock, and a return unit that returns to a command source that the write of the transaction has succeeded after the write by the writing unit or after the discarding of the write command by the optimizing unit.