apoorvmittal10 commented on code in PR #19148:
URL: https://github.com/apache/kafka/pull/19148#discussion_r1991048323
##########
server/src/main/java/org/apache/kafka/server/share/fetch/PartitionRotateStrategy.java:
##########
@@ -80,20 +81,11 @@ static LinkedHashMap<TopicIdPartition, Integer>
rotateRoundRobin(
return topicIdPartitions;
}
- // TODO: Once the partition max bytes is removed then the partition
will be a linked list and rotation
- // will be a simple operation. Else consider using
ImplicitLinkedHashCollection.
- LinkedHashMap<TopicIdPartition, Integer> suffixPartitions = new
LinkedHashMap<>(rotateAt);
- LinkedHashMap<TopicIdPartition, Integer> rotatedPartitions = new
LinkedHashMap<>(topicIdPartitions.size());
- int i = 0;
- for (Map.Entry<TopicIdPartition, Integer> entry :
topicIdPartitions.entrySet()) {
- if (i < rotateAt) {
- suffixPartitions.put(entry.getKey(), entry.getValue());
- } else {
- rotatedPartitions.put(entry.getKey(), entry.getValue());
- }
- i++;
- }
- rotatedPartitions.putAll(suffixPartitions);
+ // We don't want to modify the original list, hence created a copy.
+ List<TopicIdPartition> rotatedPartitions = new
ArrayList<>(topicIdPartitions);
+ // We want the elements from the end of the list to move left by the
distance provided i.e. if the original list is [1,2,3],
+ // and we want to rotate it by 1, we want the output as [2,3,1] and
not [3,1,2]. Hence, we need negation of distance here.
Review Comment:
```suggestion
// Elements from the list should move left by the distance provided
i.e. if the original list is [1,2,3],
// and rotation is by 1, then output should be [2,3,1] and not
[3,1,2]. Hence, negate the distance here.
```
##########
server/src/test/java/org/apache/kafka/server/share/fetch/PartitionRotateStrategyTest.java:
##########
@@ -35,64 +36,64 @@ public class PartitionRotateStrategyTest {
@Test
public void testRoundRobinStrategy() {
PartitionRotateStrategy strategy =
PartitionRotateStrategy.type(StrategyType.ROUND_ROBIN);
- LinkedHashMap<TopicIdPartition, Integer> partitions =
createPartitions(3);
+ List<TopicIdPartition> partitions = createPartitions(3);
- LinkedHashMap<TopicIdPartition, Integer> result =
strategy.rotate(partitions, new PartitionRotateMetadata(1));
+ List<TopicIdPartition> result = strategy.rotate(partitions, new
PartitionRotateMetadata(1));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 1);
+ validateRotatedListEquals(partitions, result, 1);
// Session epoch is greater than the number of partitions.
result = strategy.rotate(partitions, new PartitionRotateMetadata(5));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 2);
+ validateRotatedListEquals(partitions, result, 2);
// Session epoch is at Integer.MAX_VALUE.
result = strategy.rotate(partitions, new
PartitionRotateMetadata(Integer.MAX_VALUE));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 1);
+ validateRotatedListEquals(partitions, result, 1);
// No rotation at same size as epoch.
result = strategy.rotate(partitions, new PartitionRotateMetadata(3));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 0);
+ validateRotatedListEquals(partitions, result, 0);
}
@Test
public void testRoundRobinStrategyWithSpecialSessionEpochs() {
PartitionRotateStrategy strategy =
PartitionRotateStrategy.type(StrategyType.ROUND_ROBIN);
- LinkedHashMap<TopicIdPartition, Integer> partitions =
createPartitions(3);
- LinkedHashMap<TopicIdPartition, Integer> result = strategy.rotate(
+ List<TopicIdPartition> partitions = createPartitions(3);
+ List<TopicIdPartition> result = strategy.rotate(
partitions,
new PartitionRotateMetadata(ShareRequestMetadata.INITIAL_EPOCH));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 0);
+ validateRotatedListEquals(partitions, result, 0);
result = strategy.rotate(
partitions,
new PartitionRotateMetadata(ShareRequestMetadata.FINAL_EPOCH));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 0);
+ validateRotatedListEquals(partitions, result, 0);
}
@Test
public void testRoundRobinStrategyWithEmptyPartitions() {
PartitionRotateStrategy strategy =
PartitionRotateStrategy.type(StrategyType.ROUND_ROBIN);
// Empty partitions.
- LinkedHashMap<TopicIdPartition, Integer> result = strategy.rotate(new
LinkedHashMap<>(), new PartitionRotateMetadata(5));
+ List<TopicIdPartition> result = strategy.rotate(new ArrayList<>(), new
PartitionRotateMetadata(5));
// The result should be empty.
assertTrue(result.isEmpty());
}
/**
- * Create an ordered map of TopicIdPartition to partition max bytes.
+ * Create an ordered set of topic partitions.
Review Comment:
```suggestion
* Create a list of topic partitions.
```
##########
server/src/test/java/org/apache/kafka/server/share/fetch/PartitionRotateStrategyTest.java:
##########
@@ -35,64 +36,64 @@ public class PartitionRotateStrategyTest {
@Test
public void testRoundRobinStrategy() {
PartitionRotateStrategy strategy =
PartitionRotateStrategy.type(StrategyType.ROUND_ROBIN);
- LinkedHashMap<TopicIdPartition, Integer> partitions =
createPartitions(3);
+ List<TopicIdPartition> partitions = createPartitions(3);
- LinkedHashMap<TopicIdPartition, Integer> result =
strategy.rotate(partitions, new PartitionRotateMetadata(1));
+ List<TopicIdPartition> result = strategy.rotate(partitions, new
PartitionRotateMetadata(1));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 1);
+ validateRotatedListEquals(partitions, result, 1);
// Session epoch is greater than the number of partitions.
result = strategy.rotate(partitions, new PartitionRotateMetadata(5));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 2);
+ validateRotatedListEquals(partitions, result, 2);
// Session epoch is at Integer.MAX_VALUE.
result = strategy.rotate(partitions, new
PartitionRotateMetadata(Integer.MAX_VALUE));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 1);
+ validateRotatedListEquals(partitions, result, 1);
// No rotation at same size as epoch.
result = strategy.rotate(partitions, new PartitionRotateMetadata(3));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 0);
+ validateRotatedListEquals(partitions, result, 0);
}
@Test
public void testRoundRobinStrategyWithSpecialSessionEpochs() {
PartitionRotateStrategy strategy =
PartitionRotateStrategy.type(StrategyType.ROUND_ROBIN);
- LinkedHashMap<TopicIdPartition, Integer> partitions =
createPartitions(3);
- LinkedHashMap<TopicIdPartition, Integer> result = strategy.rotate(
+ List<TopicIdPartition> partitions = createPartitions(3);
+ List<TopicIdPartition> result = strategy.rotate(
partitions,
new PartitionRotateMetadata(ShareRequestMetadata.INITIAL_EPOCH));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 0);
+ validateRotatedListEquals(partitions, result, 0);
result = strategy.rotate(
partitions,
new PartitionRotateMetadata(ShareRequestMetadata.FINAL_EPOCH));
assertEquals(3, result.size());
- validateRotatedMapEquals(partitions, result, 0);
+ validateRotatedListEquals(partitions, result, 0);
}
@Test
public void testRoundRobinStrategyWithEmptyPartitions() {
PartitionRotateStrategy strategy =
PartitionRotateStrategy.type(StrategyType.ROUND_ROBIN);
// Empty partitions.
- LinkedHashMap<TopicIdPartition, Integer> result = strategy.rotate(new
LinkedHashMap<>(), new PartitionRotateMetadata(5));
+ List<TopicIdPartition> result = strategy.rotate(new ArrayList<>(), new
PartitionRotateMetadata(5));
// The result should be empty.
assertTrue(result.isEmpty());
}
/**
- * Create an ordered map of TopicIdPartition to partition max bytes.
+ * Create an ordered set of topic partitions.
* @param size The number of topic-partitions to create.
- * @return The ordered map of TopicIdPartition to partition max bytes.
+ * @return The ordered set of topic partitions.
Review Comment:
```suggestion
* @return The list of topic partitions.
```
##########
server/src/main/java/org/apache/kafka/server/share/fetch/PartitionRotateStrategy.java:
##########
@@ -80,20 +81,11 @@ static LinkedHashMap<TopicIdPartition, Integer>
rotateRoundRobin(
return topicIdPartitions;
}
- // TODO: Once the partition max bytes is removed then the partition
will be a linked list and rotation
- // will be a simple operation. Else consider using
ImplicitLinkedHashCollection.
- LinkedHashMap<TopicIdPartition, Integer> suffixPartitions = new
LinkedHashMap<>(rotateAt);
- LinkedHashMap<TopicIdPartition, Integer> rotatedPartitions = new
LinkedHashMap<>(topicIdPartitions.size());
- int i = 0;
- for (Map.Entry<TopicIdPartition, Integer> entry :
topicIdPartitions.entrySet()) {
- if (i < rotateAt) {
- suffixPartitions.put(entry.getKey(), entry.getValue());
- } else {
- rotatedPartitions.put(entry.getKey(), entry.getValue());
- }
- i++;
- }
- rotatedPartitions.putAll(suffixPartitions);
+ // We don't want to modify the original list, hence created a copy.
Review Comment:
```suggestion
// Avoid modifying the original list, create copy.
```
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