Described is a method comprising initializing a first set of bits corresponding to a first plurality of predicate indices to a first value, and initializing a second set of bits corresponding to a second plurality of predicate indices to a second value. A subscription is processed. The subscription includes a plurality of subscription predicates, each of the subscription predicates associated with corresponding predicate indices in one of the first and second pluralities. An event is processed. The event includes an event predicate. When the event predicate matches a first predicate index in the first plurality, a first bit associated with the first predicate index is toggled to the second value. When the event predicate matches a second predicate index in the second plurality, a second bit associated with the second predicate index is toggled to the first value. When each bit associated with the corresponding predicate indices is the second value, the event is outputted to a source of the subscription.