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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.search.predicate.benchmarks;
import java.util.Map;
/**
* Various metrics stored during query execution
*
* @author bjorncs
*/
public class ResultMetrics {
private static final int MAX_LATENCY = 100; // ms
private static final int RESOLUTION = 25; // sample points per ms
private static final int SLOTS = MAX_LATENCY * RESOLUTION;
private long totalQueries = 0;
private long totalHits = 0;
private double maxLatency = Double.MIN_VALUE;
private double minLatency = Double.MAX_VALUE;
private final long[] latencyHistogram = new long[SLOTS];
public void registerResult(long hits, double latencyMilliseconds) {
if (latencyMilliseconds > maxLatency) {
maxLatency = latencyMilliseconds;
}
if (latencyMilliseconds < minLatency) {
minLatency = latencyMilliseconds;
}
totalHits += hits;
++totalQueries;
int latencySlot = (int) Math.round(latencyMilliseconds * RESOLUTION);
// Note: extreme latency values are ignored in the histogram for simplicity
if (latencySlot < SLOTS) {
++latencyHistogram[latencySlot];
}
}
public void combine(ResultMetrics other) {
totalQueries += other.totalQueries;
minLatency = Math.min(minLatency, other.minLatency);
maxLatency = Math.max(maxLatency, other.maxLatency);
totalHits += other.totalHits;
for (int i = 0; i < SLOTS; i++) {
latencyHistogram[i] += other.latencyHistogram[i];
}
}
public void writeMetrics(Map<String, Object> metricMap, long timeSearch) {
double qps = timeSearch == 0 ? 0 : (1000d * totalQueries / timeSearch);
metricMap.put("QPS", qps);
metricMap.put("Time search", timeSearch);
metricMap.put("Total hits", totalHits);
metricMap.put("Total queries", totalQueries);
metricMap.put("Max latency", latencyToString(maxLatency));
metricMap.put("Min latency", latencyToString(minLatency));
metricMap.put("99.9 percentile", latencyToString(percentile(0.999)));
metricMap.put("99 percentile", latencyToString(percentile(0.99)));
metricMap.put("90 percentile", latencyToString(percentile(0.90)));
metricMap.put("75 percentile", latencyToString(percentile(0.75)));
metricMap.put("50 percentile", latencyToString(percentile(0.50)));
}
private double percentile(double percentile) {
long targetCount = Math.round(totalQueries * percentile);
long currentCount = 0;
int index = 0;
while (currentCount < targetCount && index < SLOTS) {
currentCount += latencyHistogram[index];
++index;
}
if (index == SLOTS) {
return maxLatency;
}
return toLatency(currentCount == targetCount ? index + 1 : index);
}
private static String latencyToString(double averageLatency) {
return String.format("%.2fms", averageLatency);
}
private static double toLatency(int index) {
return (index + 0.5) / (double) RESOLUTION;
}
}
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