private OptionalDouble calculateQoS(Interval interval, MetricSet metricSet) {
OptionalDouble qualityOfService = OptionalDouble.empty();
long intervalSize = interval.end() - interval.start();
double timestampsCalculated = intervalSize / metricSet.step();
log.trace("intervalSize = {}; metricSet.step() = {}", intervalSize, metricSet.step());
log.trace("metricSet should contain {} timestamps", timestampsCalculated);
if (timestampsCalculated >= 1) {
qualityOfService = OptionalDouble.of(metricSet.size() / timestampsCalculated);
}
return qualityOfService;
}
public Optional<MetricSet> getValues(String metricName, Interval interval) {
Instant now = Clock.systemUTC().instant();
Optional<RetentionLevel> accessLevel =
environment.retentions().findAccessLevelForMetric(metricName);
Optional<MetricSet> setWithHighestQoS = Optional.empty();
double highestAvailableQoS = 0;
if (!accessLevel.isPresent()) {
return Optional.empty();
}
EvictionStrategy evictionStrategy = findEvictionStrategyForAccessLevel(accessLevel.get()).get();
evictionStrategy.accessing(metricName);
while (accessLevel.isPresent() && caches.containsKey(accessLevel.get().name())) {
log.trace("Found accessLevel " + accessLevel.get().name());
Optional<CachingLevel> cachingLevel =
environment.cachingConfiguration().findLevelForLevelName(accessLevel.get().name());
if (cachingLevel.isPresent()) {
long cachingLevelStart =
now.minusSeconds(cachingLevel.get().cacheLineWidth() * accessLevel.get().frequency())
.getEpochSecond();
if (cachingLevelStart < interval.start()) {
Optional<MetricSet> metricSet = doGetValues(metricName, interval, cachingLevel.get());
if (!metricSet.isPresent()) {
try {
createNewCacheLines(metricName).get();
} catch (InterruptedException | ExecutionException e) {
log.warn("Exception while waiting for threads loading metrics", e);
}
metricSet = doGetValues(metricName, interval, cachingLevel.get());
}
if (metricSet.isPresent()) {
log.trace("metricSet contains {} timestamps", metricSet.get().size());
log.trace("accesslevel: {} | metricSet: {}", accessLevel.get().name(), metricSet.get());
OptionalDouble serviceAvailable = calculateQoS(interval, metricSet.get());
if (serviceAvailable.isPresent()
&& serviceAvailable.getAsDouble()
>= environment.cachingConfiguration().qualityOfService()) {
log.trace("returning metricSet");
return metricSet;
} else if (serviceAvailable.isPresent()
&& serviceAvailable.getAsDouble() > highestAvailableQoS) {
log.trace("new highestAvailable set");
highestAvailableQoS = serviceAvailable.getAsDouble();
setWithHighestQoS = metricSet;
}
} else {
log.debug(
"no metricSet for cacheLevel {} metric {} found!",
accessLevel.get().name(),
metricName);
}
}
}
accessLevel = environment.retentions().getNextLevel(accessLevel.get());
}
log.trace("service requested not available, returning highest available");
return setWithHighestQoS;
}