In sharded storage implementations it's common for a request to one node to be forwarded to another node, e.g. Cassandra's coordinator node can talk to other nodes. The trace view currently colors spans by the service name only, so calls between different instances of the same service are colored the same, making it harder to understand without expanding the spans.
Some options to fix this:
- take process hostname / ip into account when assigning the color
- add an optional column Hostname to the grid
- decorate service name to indicate different instances, e.g.
cassandra[1], cassandra[2]
- decorate service name with host name
cassandra[host-001] if there are multiple nodes involved in the trace