Method and apparatus for logging journal data in a computing apparatus.

摘要

Operation of a computing system including a data base and a log of changes to the data base is enhanced by enabling online access to log records stored both in direct access storage devices and archive log storage devices. Responsive to a request from a user of a log facility to store a log record, a sequential relative byte address is assigned to the log record and returned to the user, and the log record is stored in a main storage log buffer. The log buffer contents are periodically written to one of at least two data sets on direct access storage devices, and these data sets are offloaded selectively from the direct access storage device to an archive log device while writes of log buffer contents to the data set being offloaded are inhibited. An index of the log records is maintained in a boot strap data set, and includes the range of relative byte addresses of log records stored in each direct access storage device and archive device. Responsive to a request from a user of the log facility for a log record having a given relative byte address, the requested log record is obtained from the most accessible storage location referenced by the index.