protected <T> void metricChanged(BaseMetricImpl<T> metric) {
long lastTime = metric.changeTime;
// NOTE: changeTime is only accurate for metrics that are enabled, and
// to guarantee that it always corresponds to the value, updates to
// enabled metrics are synchronized.
metric.changeTime = timebase + System.nanoTime();
metric.valueChanged = true;
metricsDataChanged = true;
int level;
if ((lastTime == 0) || (metric.changeTime <= lastTime)) {
level = 0;
} else {
// Longer duration -> higher level.
double r = random.nextDouble();
if (r == 0) {
level = NLEVELS - 1;
} else {
level =
Math.min(
NLEVELS - 1,
(int) (Math.log((metric.changeTime - lastTime) / r) / METRIC_LEVEL_DIVISOR));
}
}
MetricLevel<T> metricLevel = metric.levels.get(level);
MetricLevelValues values = metricLevel.values.peekLast();
if ((values == null) || values.isFull()) {
if (logger.isTraceEnabled()) {
logger.trace(
"New level {} entry at {} for {}", new Object[] {level, metric.changeTime, metric});
}
values = new MetricLevelValues(metric.changeTime, metric.encodeValue());
metricLevel.values.addLast(values);
} else {
if (logger.isTraceEnabled()) {
logger.trace(
"Adding to level {} entry at {} for {}",
new Object[] {level, metric.changeTime, metric});
}
values.append(metric.encodeValue(metricLevel));
}
metricLevel.lastValue = metric.getObject();
metricLevel.lastTime = metric.changeTime;
}
protected void writeMetrics() {
boolean anyConfChanges = false;
for (BaseMetricImpl<?> metric : metrics.values()) {
if (!metric.confChanged && !metric.valueChanged) continue;
synchronized (metric) {
if (metric.confChanged) {
anyConfChanges = true;
pendingWrites.add(
new KeyValue(
confSubspace.pack(
tupleFrom(
metric.getType(), metric.getName(), address, DEFAULT_ID, ENABLED_OPTION)),
metric.enabled ? ENABLED_TRUE : ENABLED_FALSE));
metric.confChanged = false;
}
if (metric.valueChanged) {
pendingWrites.add(
new KeyValue(
dataSubspace.pack(
tupleFrom(metric.getType(), metric.getName(), address, DEFAULT_ID)),
metric.encodeValue()));
metric.valueChanged = false;
}
for (int level = 0; level < NLEVELS; level++) {
MetricLevel<?> metricLevel = metric.levels.get(level);
while (true) {
MetricLevelValues values = metricLevel.values.pollFirst();
if (values == null) break;
pendingWrites.add(
new KeyValue(
dataSubspace.pack(
tupleFrom(
metric.getType(),
metric.getName(),
address,
DEFAULT_ID,
level,
values.start)),
values.bytes));
// Continue to fill (will overwrite key with longer value).
if (metricLevel.values.isEmpty() && !values.isFull()) {
metricLevel.values.addLast(values);
break;
}
}
}
}
}
if (anyConfChanges) {
// Signal a change in configuration. We will respond to this change,
// too, but that seemd harmless and difficult to avoid in a general
// way.
byte[] bytes = new byte[16];
random.nextBytes(bytes);
if (logger.isDebugEnabled()) {
logger.debug("Writing {}: {}", METRIC_CONF_CHANGES_KEY, ByteArrayUtil.printable(bytes));
}
pendingWrites.add(new KeyValue(confChangesSubspace.getKey(), bytes));
}
if (!pendingWrites.isEmpty()) {
getDatabase()
.run(
new Function<Transaction, Void>() {
@Override
public Void apply(Transaction tr) {
tr.options().setAccessSystemKeys();
for (KeyValue kv : pendingWrites) {
tr.set(kv.getKey(), kv.getValue());
}
return null;
}
});
pendingWrites.clear();
}
}