Mastering Distributed Tracing

Identifying sources of latency

So far, we have not discussed the performance characteristics of the HotROD application. If we refer to Figure 2.6, we can easily make the following conclusions:

1. The call to the customer service is on the critical path because no other work can be done until we get back the customer data that includes the location to which we need to dispatch the car.
2. The driver service retrieves N nearest drivers given the customer's location and then queries Redis for each driver's data in a sequence, which can be seen in the staircase pattern of Redis GetDriver spans. If these operations can be done in parallel, the overall latency can be reduced by almost 200ms.
3. The calls to the route service are not sequential, but not fully parallel ...