  Spinlocks are widely used in database engines for processes synchronization.
KGX mutexes is new retrial spinlocks appeared in contemporary Oracle versions
for submicrosecond synchronization. The mutex contention is frequently observed
in highly concurrent OLTP environments.
  This work explores how Oracle mutexes operate, spin, and sleep. It develops
predictive mathematical model and discusses parameters and statistics related
to mutex performance tuning, as well as results of contention experiments.
