This package contains support for logical clocks (needed to prevent isolation problems). At the moment the main clock is the {@link PrimitiveClock}, but in the future more advanced clocks like the vector clock will be provided. The former is very very fast, but it isn't going to scale because unrelated transactions need to share the same clock. That is where vector clocks come in. Although they are a lot slower, the shared clock isn't needed anymore. The addition of the vector clock will also be the first step to creating a distributed stm (a PrimitiveClock is not going to scale since the performance of a cluster is limited to the increase rate of the clock).