Patents Examined by Diane D. Mizrali
  • Patent number: 5878414
    Abstract: A method to construct a transaction serialization order based on parallel or distributed database log files that connects the log files into a network and merges the network into a sequence. Only vote symbols and commit symbols are considered in the construction and a protocol of a transaction's vote appearing before a transaction's commit is enforced. The log files are connected by making links between commit symbols of the same transactions in different log files. The method identifies ambiguities in the orders of the individual log files, called commit symbol cycles, and resolves them by breaking an unsupported segment of the cycle and sliding the segment's forwardmost commit symbol backward to a position immediately prior to the first commit symbol on that segment. By doing so, the serialization implication of an individual log file may be changed, but the overall serialization implication of the database remains intact. Using an iterative process, this method can order the log files in one pass-through.
    Type: Grant
    Filed: June 6, 1997
    Date of Patent: March 2, 1999
    Assignee: International Business Machines Corp.
    Inventors: Hui-I Hsiao, Ming-Ling Lo