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;
}
@Override
public void run() {
Instant now = Clock.systemUTC().instant();
Optional<RetentionLevel> accessLevel =
environment.retentions().findAccessLevelForMetric(metricName);
if (accessLevel.isPresent()) {
if (caches.get(accessLevel.get().name()).containsMetric(metricName)) {
return;
}
Optional<RetentionLevel> highestLevel = accessLevel;
while (highestLevel.isPresent() && highestLevel.get().next() != null) {
highestLevel = environment.retentions().getNextLevel(highestLevel.get());
}
Optional<CachingLevel> cachingLevel =
environment.cachingConfiguration().findLevelForLevelName(highestLevel.get().name());
if (cachingLevel.isPresent()) {
List<Future<?>> futures = new ArrayList<>();
ArrayList<Metric> databaseMetricsList = new ArrayList<>();
long intervalStart =
now.minusSeconds(cachingLevel.get().cacheLineWidth() * highestLevel.get().frequency())
.getEpochSecond();
Interval interval = new Interval(intervalStart, now.getEpochSecond());
Stream<Metric> databaseMetrics =
environment.cassandraAccessLayer().loadMetrics(metricName, interval);
Iterator<Metric> databaseMetricsIterator = databaseMetrics.iterator();
while (databaseMetricsIterator.hasNext()) {
Metric m = databaseMetricsIterator.next();
databaseMetricsList.add(m);
}
while (accessLevel.isPresent()) {
LoadMetrics loadMetrics =
new LoadMetrics(accessLevel.get(), metricName, databaseMetricsList, interval);
futures.add(loadMetricsThreadPool.submit(Executors.callable(loadMetrics)));
accessLevel = environment.retentions().getNextLevel(accessLevel.get());
}
for (Future<?> f : futures) {
try {
f.get();
} catch (InterruptedException | ExecutionException e) {
log.warn("Exception while waiting for insertion of metrics into cache", e);
}
}
}
}
log.trace("all new cache lines created for metric {}", metricName);
}