Provided is a failure recovery method for switching to a standby system if a failure occurs in an active system, which allows reduction of loads on the standby system and a network. A computer system, which receives data to which timestamp information is appended in a chronological order and processes the received data by registered queries, includes the active system for processing the received data and the standby system for processing the received data instead of the active system upon occurrence of a failure. The active system processes the received data by the respective queries according to a predefined sequence, and transmits results obtained from the received data by the respective queries to the standby system as intermediate data on a query basis at a predetermined timing. The standby system restores the data by processing the received data and the intermediate data if a failure occurs in the active system.