jsancio commented on code in PR #16518:
URL: https://github.com/apache/kafka/pull/16518#discussion_r1664928188
##########
raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java:
##########
@@ -151,6 +151,7 @@ public final class KafkaRaftClient<T> implements
RaftClient<T> {
public static final int MAX_FETCH_WAIT_MS = 500;
public static final int MAX_BATCH_SIZE_BYTES = 8 * 1024 * 1024;
public static final int MAX_FETCH_SIZE_BYTES = MAX_BATCH_SIZE_BYTES;
+ public static final OffsetAndEpoch BOOTSTRAP_SNAPSHOT_ID = new
OffsetAndEpoch(0, 0);
Review Comment:
Let's define this in `o.a.k.s.Snapshots` instead.
##########
raft/src/main/java/org/apache/kafka/raft/LeaderState.java:
##########
@@ -202,7 +214,46 @@ public void appendLeaderChangeMessage(long currentTimeMs) {
.setVoters(voters)
.setGrantingVoters(grantingVoters);
- accumulator.appendLeaderChangeMessage(leaderChangeMessage,
currentTimeMs);
+ accumulator.appendControlMessages((baseOffset, epoch, buffer) -> {
+ try (MemoryRecordsBuilder builder = new MemoryRecordsBuilder(
+ buffer,
+ RecordBatch.CURRENT_MAGIC_VALUE,
+ Compression.NONE,
+ TimestampType.CREATE_TIME,
+ baseOffset,
+ currentTimeMs,
+ RecordBatch.NO_PRODUCER_ID,
+ RecordBatch.NO_PRODUCER_EPOCH,
+ RecordBatch.NO_SEQUENCE,
+ false,
+ true,
+ epoch,
+ buffer.capacity()
+ )
+ ) {
+ builder.appendLeaderChangeMessage(
+ currentTimeMs,
+ leaderChangeMessage
+ );
+ VoterSetOffset voterSetOffset =
lastVoterSetOffset.orElse(null);
+ // if lastVoterOffset is -1 we know the leader hasn't written
the bootstrap snapshot records to the log yet
+ if (voterSetOffset != null && voterSetOffset.offset() == -1) {
Review Comment:
Avoid the use of `null`.
```java
lastVoterSetOffset.ifPresent(voterSetOffset -> {
// if lastVoterOffset is -1 we know the leader hasn't
written the bootstrap snapshot records to the log yet
if (voterSetOffset.offset() == -1) {
```
##########
raft/src/main/java/org/apache/kafka/raft/internals/VoterSetOffset.java:
##########
@@ -0,0 +1,35 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.raft.internals;
+
+public class VoterSetOffset {
+ private final VoterSet voterSet;
+ private final Long offset;
Review Comment:
An object is not needed. Use `long` instead. It takes less space and doesn't
require a dereference.
##########
raft/src/main/java/org/apache/kafka/raft/internals/VoterSetOffset.java:
##########
@@ -0,0 +1,35 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.raft.internals;
+
+public class VoterSetOffset {
Review Comment:
Why did you add this type instead of using `LogHistory.Entry<VoterSet>`?
##########
raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java:
##########
@@ -454,6 +455,7 @@ public void initialize(
nodeId,
nodeDirectoryId,
partitionState::lastVoterSet,
+ partitionState::lastVoterSetOffset,
Review Comment:
It is unfortunate that we need to add a parameter to the constructor just so
that it can pass this value to `LeaderState`. I am starting to think that
`QuorumState` should just have access to the `partitionState`
(`KRaftControlRecordStateMachine`) object.
##########
raft/src/main/java/org/apache/kafka/raft/LeaderState.java:
##########
@@ -202,7 +214,46 @@ public void appendLeaderChangeMessage(long currentTimeMs) {
.setVoters(voters)
.setGrantingVoters(grantingVoters);
- accumulator.appendLeaderChangeMessage(leaderChangeMessage,
currentTimeMs);
+ accumulator.appendControlMessages((baseOffset, epoch, buffer) -> {
+ try (MemoryRecordsBuilder builder = new MemoryRecordsBuilder(
+ buffer,
+ RecordBatch.CURRENT_MAGIC_VALUE,
+ Compression.NONE,
+ TimestampType.CREATE_TIME,
+ baseOffset,
+ currentTimeMs,
+ RecordBatch.NO_PRODUCER_ID,
+ RecordBatch.NO_PRODUCER_EPOCH,
+ RecordBatch.NO_SEQUENCE,
+ false,
+ true,
+ epoch,
+ buffer.capacity()
+ )
+ ) {
+ builder.appendLeaderChangeMessage(
+ currentTimeMs,
+ leaderChangeMessage
+ );
+ VoterSetOffset voterSetOffset =
lastVoterSetOffset.orElse(null);
+ // if lastVoterOffset is -1 we know the leader hasn't written
the bootstrap snapshot records to the log yet
+ if (voterSetOffset != null && voterSetOffset.offset() == -1) {
+ if (kraftVersion > 0) {
Review Comment:
It is an `IllegalStateException` if a voters set exist in the bootstrap
checkpoint but the kraft.version is 0.
##########
raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java:
##########
@@ -1396,12 +1398,12 @@ private FetchResponseData tryCompleteFetchRequest(
int lastFetchedEpoch = request.lastFetchedEpoch();
LeaderState<T> state = quorum.leaderStateOrThrow();
- Optional<OffsetAndEpoch> latestSnapshotId = log.latestSnapshotId();
+ OffsetAndEpoch latestSnapshotId =
log.latestSnapshotId().orElse(null);
final ValidOffsetAndEpoch validOffsetAndEpoch;
- if (fetchOffset == 0 && latestSnapshotId.isPresent()) {
- // If the follower has an empty log and a snapshot exist, it
is always more efficient
+ if (fetchOffset == 0 && latestSnapshotId != null &&
!latestSnapshotId.equals(BOOTSTRAP_SNAPSHOT_ID)) {
Review Comment:
Let's avoid the use of `null`.
```java
if (fetchOffset == 0 &&
latestSnapshotId.isPresent() &&
!latestSnapshotId.get().equals(BOOTSTRAP_SNAPSHOT_ID)
) {
```
Reference:
https://www.infoq.com/presentations/Null-References-The-Billion-Dollar-Mistake-Tony-Hoare/
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