private boolean shouldTraceQuery(Query query) {
        // Only trace for explicit bucket subset queries, as otherwise we'd get a trace entry for every superbucket in the system.
        return (queryIsLocationConstrained(query) &&
                ((query.getTrace().getLevel() > 0) || tracingOptions.getSamplingStrategy().shouldSample()));
    }
The route to the storage cluster.
container-search/src/main/java/com/yahoo/vespa/streamingvisitors/StreamingBackend.java