Logging System Performance Improvements

A number of improvements to the logging system eliminate or at least minimize bottlenecks identified when running various performance tests. These changes include elimination of contentious current_llb_mutex, faster log forces through forcing only what needs forcing, and improved concurrency potential (fast resume).

Buffer Manager Performance Improvements

A number of improvements have been made to the buffer manager to eliminate or minimize bottlenecks identified when running various performance tests. These include:

• Removal of stats for fixed priority pages. In Ingres 2.6, stats are tracked by buffer page type for better analysis of the BM's LRU algorithm.
• Raising a buffer's priority each time it is fixed; previously it was raised only when newly fixed.