Data management method and node apparatus

摘要

When receiving a predetermined command regarding an assigned key to a node apparatus, a history element is registered, which includes a first Logical Clock Value (LCV) at a first time the predetermined command was received, and a data value at a second time represented by the first LCV. When receiving a reference request to reference a data value at a third time represented by a specific LCV, a first marker is registered, which includes, as the specific LCV, a second LCV at a time when the reference request was received or a third LCV designated by the reference request, and further includes information concerning the reference request. When a fixed LCV in a system becomes not less than the specific LCV, a data value corresponding to the assigned key at the third time is identified from the history elements including first LCVs that are not greater than the specific LCV.

主权项

1. A computer-readable, non-transitory storage medium storing a program for causing a node apparatus to execute a procedure, the procedure comprising:
upon receipt of a predetermined command relating to an assigned key that is a key of which the node apparatus is in charge among a plurality of keys, first registering, into a first storage unit, a history element including a first logical clock value at a first time when the predetermined command was received, and a data value at a second time represented by the first logical clock value or information concerning the predetermined command; upon receipt of a reference request to reference a data value at a third time represented by a specific logical clock value, second registering, into the first storage unit or a second storage unit different from the first storage unit, a first marker that includes, as the specific logical clock value, a second logical clock value at a fourth time when the reference request was received or a third logical lock value designated by the reference request, and further includes information concerning the reference request; and upon detecting that a fixed clock value in a system to which the node apparatus belongs becomes equal to or greater than the specific logical clock value included in the first marker stored in the first storage unit or the second storage unit, identifying a data value corresponding to the assigned key at the third time from the history elements including first logical clock values that are equal to or less than the specific logical clock value in the first storage unit.