METHOD FOR MAINTAINING LOG COMPATIBILITY IN DATABASE SYSTEMS

A relational database system providing improved data structures and methods which operate for translating log records is described. A table of translation functions or methods (pointers) is provided, one per "logop" (i.e., log operation) record type. The logop, which is a single byte value, can be used as an index into the table. During times when a log incompatibility state exists in a database, a Log Compatibility module is invoked for performing appropriate translations. In the client's stack space, hidden from client code, a buffer is provided in which a reformatted log record can be stored. An appropriate translate method installed for the current logop is called; it procures a pointer to that buffer, and reformats the log record into that space. The system returns to the client a pointer to a reformatted log record in its own stack space, with the client largely unaware of the issue. Thus, each logop code indexes (in natural order) into an array or table which, in turn, references particular methods which perform appropriate translation, with the client (caller) receiving a pointer to the translated log record in the client's stack space.