2 * Copyright (c) 2019 Pantheon Technologies, s.r.o. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.controller.akka.segjournal;
10 import static com.google.common.base.Verify.verify;
11 import static com.google.common.base.Verify.verifyNotNull;
12 import static java.util.Objects.requireNonNull;
14 import akka.actor.AbstractActor;
15 import akka.actor.Props;
16 import akka.persistence.AtomicWrite;
17 import akka.persistence.PersistentRepr;
18 import com.codahale.metrics.Histogram;
19 import com.codahale.metrics.Meter;
20 import com.codahale.metrics.SlidingTimeWindowReservoir;
21 import com.codahale.metrics.Timer;
22 import com.google.common.base.MoreObjects;
23 import io.atomix.storage.StorageLevel;
24 import io.atomix.storage.journal.Indexed;
25 import io.atomix.storage.journal.SegmentedJournal;
26 import io.atomix.storage.journal.SegmentedJournalReader;
27 import io.atomix.storage.journal.SegmentedJournalWriter;
28 import io.atomix.utils.serializer.Namespace;
30 import java.io.Serializable;
31 import java.util.ArrayList;
32 import java.util.List;
33 import java.util.Optional;
34 import java.util.concurrent.TimeUnit;
35 import java.util.function.Consumer;
36 import org.opendaylight.controller.akka.segjournal.DataJournalEntry.FromPersistence;
37 import org.opendaylight.controller.akka.segjournal.DataJournalEntry.ToPersistence;
38 import org.slf4j.Logger;
39 import org.slf4j.LoggerFactory;
40 import scala.collection.Iterator;
41 import scala.collection.SeqLike;
42 import scala.concurrent.Future;
43 import scala.concurrent.Promise;
46 * This actor handles a single PersistentActor's journal. The journal is split into two {@link SegmentedJournal}s:
48 * <li>A memory-mapped data journal, containing actual data entries</li>
49 * <li>A simple file journal, containing sequence numbers of last deleted entry</li>
53 * This is a conscious design decision to minimize the amount of data that is being stored in the data journal while
54 * speeding up normal operations. Since the SegmentedJournal is an append-only linear log and Akka requires the ability
55 * to delete persistence entries, we need ability to mark a subset of a SegmentedJournal as deleted. While we could
56 * treat such delete requests as normal events, this leads to a mismatch between SegmentedJournal indices (as exposed by
57 * {@link Indexed}) and Akka sequence numbers -- requiring us to potentially perform costly deserialization to find the
58 * index corresponding to a particular sequence number, or maintain moderately-complex logic and data structures to
59 * perform that mapping in sub-linear time complexity.
62 * Split-file approach allows us to treat sequence numbers and indices as equivalent, without maintaining any explicit
63 * mapping information. The only additional information we need to maintain is the last deleted sequence number.
65 * @author Robert Varga
67 final class SegmentedJournalActor extends AbstractActor {
68 abstract static class AsyncMessage<T> {
69 final Promise<T> promise = Promise.apply();
72 private static final class ReadHighestSequenceNr extends AsyncMessage<Long> {
73 private final long fromSequenceNr;
75 ReadHighestSequenceNr(final long fromSequenceNr) {
76 this.fromSequenceNr = fromSequenceNr;
80 public String toString() {
81 return MoreObjects.toStringHelper(this).add("fromSequenceNr", fromSequenceNr).toString();
85 private static final class ReplayMessages extends AsyncMessage<Void> {
86 private final long fromSequenceNr;
87 private final long toSequenceNr;
88 private final long max;
89 private final Consumer<PersistentRepr> replayCallback;
91 ReplayMessages(final long fromSequenceNr,
92 final long toSequenceNr, final long max, final Consumer<PersistentRepr> replayCallback) {
93 this.fromSequenceNr = fromSequenceNr;
94 this.toSequenceNr = toSequenceNr;
96 this.replayCallback = requireNonNull(replayCallback);
100 public String toString() {
101 return MoreObjects.toStringHelper(this).add("fromSequenceNr", fromSequenceNr)
102 .add("toSequenceNr", toSequenceNr).add("max", max).toString();
106 static final class WriteMessages {
107 private final List<AtomicWrite> requests = new ArrayList<>();
108 private final List<Promise<Optional<Exception>>> results = new ArrayList<>();
110 Future<Optional<Exception>> add(final AtomicWrite write) {
111 final Promise<Optional<Exception>> promise = Promise.apply();
113 results.add(promise);
114 return promise.future();
118 public String toString() {
119 return MoreObjects.toStringHelper(this).add("requests", requests).toString();
123 private static final class DeleteMessagesTo extends AsyncMessage<Void> {
124 final long toSequenceNr;
126 DeleteMessagesTo(final long toSequenceNr) {
127 this.toSequenceNr = toSequenceNr;
131 public String toString() {
132 return MoreObjects.toStringHelper(this).add("toSequenceNr", toSequenceNr).toString();
136 private static final Logger LOG = LoggerFactory.getLogger(SegmentedJournalActor.class);
137 private static final Namespace DELETE_NAMESPACE = Namespace.builder().register(Long.class).build();
138 private static final int DELETE_SEGMENT_SIZE = 64 * 1024;
140 // Tracks the time it took us to write a batch of messages
141 private final Timer batchWriteTime = new Timer();
142 // Tracks the number of individual messages written
143 private final Meter messageWriteCount = new Meter();
144 // Tracks the size distribution of messages for last 5 minutes
145 private final Histogram messageSize = new Histogram(new SlidingTimeWindowReservoir(5, TimeUnit.MINUTES));
147 private final String persistenceId;
148 private final StorageLevel storage;
149 private final int maxSegmentSize;
150 private final int maxEntrySize;
151 private final File directory;
153 private SegmentedJournal<DataJournalEntry> dataJournal;
154 private SegmentedJournal<Long> deleteJournal;
155 private long lastDelete;
157 // Tracks largest message size we have observed either during recovery or during write
158 private int largestObservedSize;
160 SegmentedJournalActor(final String persistenceId, final File directory, final StorageLevel storage,
161 final int maxEntrySize, final int maxSegmentSize) {
162 this.persistenceId = requireNonNull(persistenceId);
163 this.directory = requireNonNull(directory);
164 this.storage = requireNonNull(storage);
165 this.maxEntrySize = maxEntrySize;
166 this.maxSegmentSize = maxSegmentSize;
169 static Props props(final String persistenceId, final File directory, final StorageLevel storage,
170 final int maxEntrySize, final int maxSegmentSize) {
171 return Props.create(SegmentedJournalActor.class, requireNonNull(persistenceId), directory, storage,
172 maxEntrySize, maxSegmentSize);
176 public Receive createReceive() {
177 return receiveBuilder()
178 .match(DeleteMessagesTo.class, this::handleDeleteMessagesTo)
179 .match(ReadHighestSequenceNr.class, this::handleReadHighestSequenceNr)
180 .match(ReplayMessages.class, this::handleReplayMessages)
181 .match(WriteMessages.class, this::handleWriteMessages)
182 .matchAny(this::handleUnknown)
187 public void preStart() throws Exception {
188 LOG.debug("{}: actor starting", persistenceId);
193 public void postStop() throws Exception {
194 LOG.debug("{}: actor stopping", persistenceId);
195 if (dataJournal != null) {
197 LOG.debug("{}: data journal closed", persistenceId);
200 if (deleteJournal != null) {
201 deleteJournal.close();
202 LOG.debug("{}: delete journal closed", persistenceId);
203 deleteJournal = null;
205 LOG.debug("{}: actor stopped", persistenceId);
209 static AsyncMessage<Void> deleteMessagesTo(final long toSequenceNr) {
210 return new DeleteMessagesTo(toSequenceNr);
213 static AsyncMessage<Long> readHighestSequenceNr(final long fromSequenceNr) {
214 return new ReadHighestSequenceNr(fromSequenceNr);
217 static AsyncMessage<Void> replayMessages(final long fromSequenceNr, final long toSequenceNr, final long max,
218 final Consumer<PersistentRepr> replayCallback) {
219 return new ReplayMessages(fromSequenceNr, toSequenceNr, max, replayCallback);
222 private void handleDeleteMessagesTo(final DeleteMessagesTo message) {
225 LOG.debug("{}: delete messages {}", persistenceId, message);
226 final long to = Long.min(dataJournal.writer().getLastIndex(), message.toSequenceNr);
227 LOG.debug("{}: adjusted delete to {}", persistenceId, to);
229 if (lastDelete < to) {
230 LOG.debug("{}: deleting entries up to {}", persistenceId, to);
233 final SegmentedJournalWriter<Long> deleteWriter = deleteJournal.writer();
234 final Indexed<Long> entry = deleteWriter.append(lastDelete);
235 deleteWriter.commit(entry.index());
236 dataJournal.writer().commit(lastDelete);
238 LOG.debug("{}: compaction started", persistenceId);
239 dataJournal.compact(lastDelete + 1);
240 deleteJournal.compact(entry.index());
241 LOG.debug("{}: compaction finished", persistenceId);
243 LOG.debug("{}: entries up to {} already deleted", persistenceId, lastDelete);
246 message.promise.success(null);
249 @SuppressWarnings("checkstyle:illegalCatch")
250 private void handleReadHighestSequenceNr(final ReadHighestSequenceNr message) {
251 LOG.debug("{}: looking for highest sequence on {}", persistenceId, message);
253 if (directory.isDirectory()) {
255 sequence = dataJournal.writer().getLastIndex();
260 LOG.debug("{}: highest sequence is {}", message, sequence);
261 message.promise.success(sequence);
264 @SuppressWarnings("checkstyle:illegalCatch")
265 private void handleReplayMessages(final ReplayMessages message) {
266 LOG.debug("{}: replaying messages {}", persistenceId, message);
269 final long from = Long.max(lastDelete + 1, message.fromSequenceNr);
270 LOG.debug("{}: adjusted fromSequenceNr to {}", persistenceId, from);
272 try (SegmentedJournalReader<DataJournalEntry> reader = dataJournal.openReader(from)) {
274 while (reader.hasNext() && count < message.max) {
275 final Indexed<DataJournalEntry> next = reader.next();
276 if (next.index() > message.toSequenceNr) {
280 LOG.trace("{}: replay {}", persistenceId, next);
281 updateLargestSize(next.size());
282 final DataJournalEntry entry = next.entry();
283 verify(entry instanceof FromPersistence, "Unexpected entry %s", entry);
285 final PersistentRepr repr = ((FromPersistence) entry).toRepr(persistenceId, next.index());
286 LOG.debug("{}: replaying {}", persistenceId, repr);
287 message.replayCallback.accept(repr);
290 LOG.debug("{}: successfully replayed {} entries", persistenceId, count);
291 } catch (Exception e) {
292 LOG.warn("{}: failed to replay messages for {}", persistenceId, message, e);
293 message.promise.failure(e);
295 message.promise.success(null);
299 @SuppressWarnings("checkstyle:illegalCatch")
300 private void handleWriteMessages(final WriteMessages message) {
303 final SegmentedJournalWriter<DataJournalEntry> writer = dataJournal.writer();
304 final long startTicks = System.nanoTime();
305 final int count = message.requests.size();
306 final long start = writer.getLastIndex();
308 for (int i = 0; i < count; ++i) {
309 final long mark = writer.getLastIndex();
311 writeRequest(writer, message.requests.get(i));
312 } catch (Exception e) {
313 LOG.warn("{}: failed to write out request", persistenceId, e);
314 message.results.get(i).success(Optional.of(e));
315 writer.truncate(mark);
319 message.results.get(i).success(Optional.empty());
322 batchWriteTime.update(System.nanoTime() - startTicks, TimeUnit.NANOSECONDS);
323 messageWriteCount.mark(writer.getLastIndex() - start);
326 private void writeRequest(final SegmentedJournalWriter<DataJournalEntry> writer, final AtomicWrite request) {
327 // Cast is needed for Eclipse because of https://bugs.eclipse.org/bugs/show_bug.cgi?id=468276
328 final Iterator<PersistentRepr> it = ((SeqLike<PersistentRepr, ?>) request.payload()).iterator();
329 while (it.hasNext()) {
330 final PersistentRepr repr = it.next();
331 final Object payload = repr.payload();
332 if (!(payload instanceof Serializable)) {
333 throw new UnsupportedOperationException("Non-serializable payload encountered " + payload.getClass());
336 final int size = writer.append(new ToPersistence(repr)).size();
337 messageSize.update(size);
338 updateLargestSize(size);
342 private void handleUnknown(final Object message) {
343 LOG.error("{}: Received unknown message {}", persistenceId, message);
346 private void updateLargestSize(final int size) {
347 if (size > largestObservedSize) {
348 largestObservedSize = size;
352 private void ensureOpen() {
353 if (dataJournal != null) {
354 verifyNotNull(deleteJournal);
358 deleteJournal = SegmentedJournal.<Long>builder().withDirectory(directory).withName("delete")
359 .withNamespace(DELETE_NAMESPACE).withMaxSegmentSize(DELETE_SEGMENT_SIZE).build();
360 final Indexed<Long> lastEntry = deleteJournal.writer().getLastEntry();
361 lastDelete = lastEntry == null ? 0 : lastEntry.entry();
363 dataJournal = SegmentedJournal.<DataJournalEntry>builder()
364 .withStorageLevel(storage).withDirectory(directory).withName("data")
365 .withNamespace(Namespace.builder()
366 .register(new DataJournalEntrySerializer(context().system()),
367 FromPersistence.class, ToPersistence.class)
369 .withMaxEntrySize(maxEntrySize).withMaxSegmentSize(maxSegmentSize)
371 final SegmentedJournalWriter<DataJournalEntry> writer = dataJournal.writer();
372 writer.commit(lastDelete);
373 LOG.debug("{}: journal open with last index {}, deleted to {}", persistenceId, writer.getLastIndex(),