Streams ACS events (active contracts) in a two step process consisting of: 1) fetching event sequential ids of the active contracts based on the filtering constraints, 2) fetching the active contracts based on the fetched event sequential ids.

Details: An input filtering constraint (consisting of parties and template ids) is converted into decomposed filtering constraints (a constraint with exactly one party and at most one template id). For each decomposed filter, the matching event sequential ids are fetched in parallel and then merged into a strictly increasing sequence. The elements from this sequence are then batched and the batch ids serve as the input to the payload fetching step.