How to query a 500MB trace?

That is a fantastically large trace. At Grafana we increase the grpc send limits for similar reasons.

server:
    grpc_server_max_recv_msg_size: 1.572864e+07
    grpc_server_max_send_msg_size: 1.572864e+07

Tempo uses the weaveworks grpc/http server. All config options are available here: