zipkin: Elasticsearch http slow on getting span names when there's a lot of data

from @dragontree101

because of we have lots of data, service name and span name all time out, i remember store data in cassandra, have table only store service_name and span_name, but store in es, service_name and span_name get by es, so time is very long.

and chrome console have

i found i set SELF_TRACING_ENABLED=“true” in environment

and yestoday’s es index is

health status index                           uuid                   pri rep docs.count docs.deleted store.size pri.store.size
green  open   zipkin-2016-12-29               2_uXTThATbyoJ7khnXbo4g   5   1  609199726            0      140gb           70gb