Patent ID: 7483920

Claim:
A method for determining consistency in a hierarchical database, the hierarchical database including a plurality of segment data with each segment data being identified by a retention address and having one or more pointers to other segment data, the method comprising: sequentially reading the one or more pointers of each segment data from the hierarchical database; generating an address hash value of retention addresses of the segment data already read; generating a pointer hash value of the pointers included in the segment data already read; correcting the address hash value when a given segment data already read is deleted or when new segment data is added to the segment data already read; correcting the pointer hash value when the given segment data already read is deleted or when the new segment data is added to the segment data already read; writing a null value in a pre-change record for an address corresponding to said new segment data; determining that the hierarchical database is consistent if the corrected address hash value coincides with the corrected pointer hash value; locking a lock for said segment data already read prior to reading for determining consistency; said locking exclusively allowing either read or write; updating, in response to split update of said segment data already read, an update history record responsive to a valid value in a read-completed address, said updating performed by first checking if said new segment data is recorded at an address higher than the read-completed address; and releasing said lock after said segment data already read is read for consistency.