使用 java 分析 neo4j 数据库命中

Question

I am trying to profile neo4j database hits using the following code

public int calculateHits(List<ExecutionPlanDescription> list) {
    int hits = 0;
    int head = 0;
    if (list.isEmpty())
        return 0;

    if (list.get(head).hasProfilerStatistics()) {
        hits += list.get(head).getProfilerStatistics().getDbHits();
        System.out.println(hits);
    }
    hits += calculateHits(list.get(head).getChildren()); // recurse over the children of the head
    list.remove(head); // remove the head to recurse on the remaining of the list
    hits += calculateHits(list);
    return hits;
}

in main I call it this way

Result result = neo4jGraph.execute(query);

int hits = calculateHits(result.getExecutionPlanDescription().getChildren()); 

However, the method always returns 0 hits. I logged the names of queryExecuter plans and found EagerAggregation, Filter. Expand(All), Filter, and NodeByLabelScan plans. But seems that profilerStatistics do not exist for all the plans as it never accesses the condition and increases the hits.

Is there any problem in the code or I need to make certain configuration first to profile the DB hits? ... appreciate your help. Thanks!

Answer 1

I figured out the problem finally! I have to use profile in the query to fill the statistics and get the DB hits. so the query should be

PROFILE Match (e:Event)-[r:has_metadata]-> (s:EventMetadata) where s.type STARTS WITH 'ELec' AND s.eventLocation IN ["GW", "GW32", "FW", "FW29" , "SW", "SW00"] AND e.date="1/11/2016" return SUM( e.reading)}