
Preface
Relational database systems have evolved significantly since their incep-
tion over 30 years ago. New applications are now more complex than ever,
and tuning a production system for performance has become a critical yet
time-consuming activity. Due to the increasing complexity in both application
workloads and query engines, even experienced database administrators (or
DBAs) cannot fully understand the ramifications of tuning decisions through-
out the whole system. As a consequence, the industry began providing auto-
mated tuning tools that systematically explore the space of alternatives and
guide DBAs. A critical element of such tuning is