A cache module responds to an operation request, from a front end, for long relation chain data of a user, and synchronously sends a modification request in the operation request to a receiving module; the receiving module receives the modification request from the cache module, and synchronously stores the modification request into an operation log file of a storage device; a saving module reads the modification request in the operation log file of the receiving module, and modifies the long relation chain data in a database (DB) according to the read modification request.