Varieties of Concurrency Control in IMS/VS Fast Path.

Fast Path supports a variety of methods of concurrency control for a vanety 0/ different uses of data. This arose naturally out of efforts to meet the typical ner~ds of large on-line transaction processing businesses. The elements of "optimistic loeking" apply to one type of data, and "group commit" appLies to all types of data. Fast Path development ex.perience supports the idea that the use of a variety of methods of concurrency control by a single transaction is reasonable and is not as difficult as might be expected, at least when there is fast access to shared memory. * This article is intended to be published in the June 1985 issue of the IEEE bulletin on Da.ta.base Engeneering.