Investigate sorting by service.name, transaction.type, service.environment

Queries for APM dashboards mostly group by service.name, transaction.type and service.environment. Sorting on these fields might speed up query performance, but it also could come at the cost of indexing performance. We can look into both to see what the trade-off here. Ideally we have a rally track at some point that will allow us to test these changes, but that might take a while, so open to other suggestions.