Information processing system for rapidly performing analysis of semistructured data while preserving fault-tolerance of data for a store request acquiring the number which has been stored of the same and data structures set beforehand, refer to data structure management information to determine a data store unit, instructs replica creation of the data with regard to the data stored in the data store unit in which any of the replicas have been stored, transmits an instruction, for performing a data operation, to a data structure operation unit, whereupon a processing unit, in accordance with the content of an analysis request, performs analysis processing by way of either data stored in any of the data storage units after a data structure operation or data which have not been subject to a data structure operation.