Fujitsu Corporation

Hiroki Moue

Nobutaka Imamura

Miho Murata

Yuichi Tsuchimoto

Toshiaki Saeki

Yasuo Yamane

Hiromichi Kobashi

A clock determination method executed by a first one of apparatuses included in a system includes receiving a list including first definite clock values of respective apparatuses, the list being circulated among the apparatuses; determining the first clock value of the first apparatus at a point in time based on a smallest of logical clock values regarding corresponding commands on which processing is not completed, the commands being included in commands received by the first apparatus and the logical clock values being obtained at a time of receiving the corresponding commands and being stored, and updating the first clock value, the updated first clock value being included in the list, by using the determined first clock value; specifying, as a second clock value for the system, a smallest of the first clock values included in the updated list; and transmitting the updated list to a second one of the apparatuses.

Method for determining definite clock and node apparatus

A first node apparatus included in a distributed data store acquires first operation information and a first timestamp corresponding to target data. The first operation information specifies a first operation to be executed on the target data. The first timestamp indicates a first receipt time of the first operation information. The first node apparatus determines whether the first receipt time is earlier than some of second receipt times on the basis of second timestamps and the acquired first timestamp. The second timestamp indicates the second receipt time of second operation information. The second operation information specifies a second operation executed on the target data. The first node apparatus re-executes the second operations together with the first operation on the target data in the order of the receipt time when it is determined that the first receipt time is earlier than some of the second receipt times.

Information processing method and information processing apparatus

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Kawasaki, Japan

Hiroki Moue