Examples with HdrHistogram org.graylog2.shared.metrics.HdrHistogram used on opensource projects

Example 1 with HdrHistogram

use of org.graylog2.shared.metrics.HdrHistogram in project graylog2-server by Graylog2.

the class JournalReader method run.

@Override
protected void run() throws Exception {
    try {
        requestedReadCount = metricRegistry.register(name(this.getClass(), "requestedReadCount"), new HdrHistogram(processBuffer.getRingBufferSize() + 1, 3));
    } catch (IllegalArgumentException e) {
        log.warn("Metric already exists", e);
        throw e;
    }
    while (isRunning()) {
        // TODO interfere with reading if we are not 100% certain we should be reading, see #listenForLifecycleChanges
        if (!shouldBeReading) {
            Uninterruptibles.sleepUninterruptibly(100, MILLISECONDS);
            // don't read immediately, but check if we should be shutting down.
            continue;
        }
        // approximate count to read from the journal to backfill the processing chain
        final long remainingCapacity = processBuffer.getRemainingCapacity();
        requestedReadCount.update(remainingCapacity);
        final List<Journal.JournalReadEntry> encodedRawMessages = journal.read(remainingCapacity);
        if (encodedRawMessages.isEmpty()) {
            log.debug("No messages to read from Journal, waiting until the writer adds more messages.");
            // block until something is written to the journal again
            try {
                readBlocked.inc();
                journalFilled.acquire();
            } catch (InterruptedException ignored) {
                // this can happen when we are blocked but the system wants to shut down. We don't have to do anything in that case.
                continue;
            }
            log.debug("Messages have been written to Journal, continuing to read.");
            // we don't care how many messages were inserted in the meantime, we'll read all of them eventually
            journalFilled.drainPermits();
        } else {
            readMessages.mark(encodedRawMessages.size());
            log.debug("Processing {} messages from journal.", encodedRawMessages.size());
            for (final Journal.JournalReadEntry encodedRawMessage : encodedRawMessages) {
                final RawMessage rawMessage = RawMessage.decode(encodedRawMessage.getPayload(), encodedRawMessage.getOffset());
                if (rawMessage == null) {
                    // never insert null objects into the ringbuffer, as that is useless
                    log.error("Found null raw message!");
                    journal.markJournalOffsetCommitted(encodedRawMessage.getOffset());
                    continue;
                }
                processBuffer.insertBlocking(rawMessage);
            }
        }
    }
    log.info("Stopping.");
}