Patent attributes
A database system and method supporting parallel update includes: a concurrency control protocol, which caches max Read Timestamp, max Write Timestamp and max Normal Write Timestamp for each data item in the database; a write-ahead log module, which records normal logs and delta logs; a cache module, which caches normal records with the largest version number of the data item and all subsequent delta records; a persistence module, which saves the records in the cache to a persistent medium; a write control module, which controls the write operation, and which, if transaction timestamp is greater than the max Read Timestamp, determine and execute normal write and incremental write respectively and generate normal records and delta records, and update the max Write Timestamp and the max Normal Write Timestamp; and a read control module maintaining a dependency graph according to dependency between the write transaction and the read transaction.
