The server device includes a cache, and identification information of data used in a previously executed transaction. The server device compares identification information of data to be used in a transaction received from a client, with the identification information held by it. When the comparison result shows a mismatch, the server device executes the transaction after updating the cache by using data acquired from a persistent storage device, while when the comparison result shows a match, the server device executes the transaction without updating the cache. Then, the server device determines whether optimistic exclusion succeeded or failed, and in the case of failure, re-executes the transaction after updating the data in the cache by using the data acquired from the persistent storage device.