Ordered Service (3.3)

Overview

The Ordered Service is required by the Ordered Routing Queue Strategy. A function defined in APL code will extract values from any routed UDR or bytearray to decide which partition queue to add it to.

Ordered Routing allows the system to utilize multicore cpus, but still have deterministic order.

Configuration of the Ordered Service

If there are session updates from a collection point that are encoded to a user-defined UDR type Ordered.Subscriber.Update with the field 'id' containing a session id, the following example shows how the values are read and added to the ordered.SessionIdentifier that the queue strategy will use to hash and select a partition based on.

import ultra.Ordered.Subscriber;
void route(ordered.SessionIdentifier si, any input) {
     if(instanceOf(input, Update)) {
         Update u = (Update)input;
         ordered.addInteger(si, u.id);
     }
}

Multiple values can be added to the SessionIdentifier, it will calculate the hash based on them all after the route function returns. If there is more than one type routed into the workflow, there must be a longer if-else chain, with a clause for each type.