Adaptable Pointer Swizzling Strategies in Object Bases: Design,
Realization, and Quantitative Analysis

A. Kemper, D. Kossmann

	   In this paper, different approaches are classified and
	   evaluated for optimizing the access to main memory resident
	   persistent objects---techniques which are commonly referred
	   to as ``pointer swizzling.'' To speed up the access along
	   inter-object references, the persistent pointers in the
	   form of unique object identifiers (OIDs) are transformed
	   (swizzled) into main memory pointers (addresses).  Pointer
	   swizzling techniques can be directed into two classes:
	   (1) strategies that allow replacement of swizzled objects
	   from the buffer before the end of an application program
	   and (2) those that outrule the displacement of swizzled
	   objects. Whereas the latter class of pointer swizzling
	   methods has received much attention in recent literature,
	   the first class---i.e., techniques that take ``precautions''
	   for the replacement of swizzled objects---has not yet been
	   thoroughly investigated. Four different pointer swizzling
	   techniques allowing object replacement were investigated and
	   contrasted them with the performance of an object manager
	   employing no pointer swizzling. The extensive qualitative
	   and quantitative evaluation---only part of which could be
	   presented in this paper---proved that there is no one superior
	   pointer swizzling strategy for all application profiles. An
	   adaptable object base run-time system was, therefore, devised
	   that employs the full range of pointer swizzling strategies
	   depending on the application profile characteristics which are
	   determined by, e.g., monitoring in combination with sampling,
	   user specifications, and/or program analysis.