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Posted to jira@kafka.apache.org by GitBox <gi...@apache.org> on 2022/03/23 10:54:10 UTC
[GitHub] [kafka] cadonna commented on a change in pull request #11760: KAFKA-13600: Kafka Streams - Fall back to most caught up client if no caught up clients exist
cadonna commented on a change in pull request #11760:
URL: https://github.com/apache/kafka/pull/11760#discussion_r833117940
##########
File path: streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/TaskMovement.java
##########
@@ -102,45 +108,27 @@ static int assignActiveTaskMovements(final Map<TaskId, SortedSet<UUID>> tasksToC
final int movementsNeeded = taskMovements.size();
for (final TaskMovement movement : taskMovements) {
- final UUID standbySourceClient = caughtUpClientsByTaskLoad.poll(
- movement.task,
- c -> clientStates.get(c).hasStandbyTask(movement.task)
- );
- if (standbySourceClient == null) {
- // there's not a caught-up standby available to take over the task, so we'll schedule a warmup instead
- final UUID sourceClient = requireNonNull(
- caughtUpClientsByTaskLoad.poll(movement.task),
- "Tried to move task to caught-up client but none exist"
- );
-
- moveActiveAndTryToWarmUp(
- remainingWarmupReplicas,
- movement.task,
- clientStates.get(sourceClient),
- clientStates.get(movement.destination),
- warmups.computeIfAbsent(movement.destination, x -> new TreeSet<>())
- );
- caughtUpClientsByTaskLoad.offerAll(asList(sourceClient, movement.destination));
- } else {
- // we found a candidate to trade standby/active state with our destination, so we don't need a warmup
- swapStandbyAndActive(
- movement.task,
- clientStates.get(standbySourceClient),
- clientStates.get(movement.destination)
- );
- caughtUpClientsByTaskLoad.offerAll(asList(standbySourceClient, movement.destination));
+ // Attempt to find a caught up standby, otherwise find any caught up client, failing that use the most
+ // caught up client.
+ final boolean moved = tryToSwapStandbyAndActiveOnCaughtUpClient(clientStates, caughtUpClientsByTaskLoad, movement) ||
+ tryToMoveActiveToCaughtUpClientAndTryToWarmUp(clientStates, warmups, remainingWarmupReplicas, caughtUpClientsByTaskLoad, movement) ||
+ tryToMoveActiveToMostCaughtUpClient(tasksToClientByLag, clientStates, warmups, remainingWarmupReplicas, caughtUpClientsByTaskLoad, movement);
+
+ if (!moved) {
+ throw new IllegalStateException("Tried to move task to more caught-up client but none exist");
Review comment:
```suggestion
throw new IllegalStateException("Tried to move task to more caught-up client as scheduled before but none exist");
```
##########
File path: streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/TaskMovement.java
##########
@@ -102,45 +108,27 @@ static int assignActiveTaskMovements(final Map<TaskId, SortedSet<UUID>> tasksToC
final int movementsNeeded = taskMovements.size();
for (final TaskMovement movement : taskMovements) {
- final UUID standbySourceClient = caughtUpClientsByTaskLoad.poll(
- movement.task,
- c -> clientStates.get(c).hasStandbyTask(movement.task)
- );
- if (standbySourceClient == null) {
- // there's not a caught-up standby available to take over the task, so we'll schedule a warmup instead
- final UUID sourceClient = requireNonNull(
- caughtUpClientsByTaskLoad.poll(movement.task),
- "Tried to move task to caught-up client but none exist"
- );
-
- moveActiveAndTryToWarmUp(
- remainingWarmupReplicas,
- movement.task,
- clientStates.get(sourceClient),
- clientStates.get(movement.destination),
- warmups.computeIfAbsent(movement.destination, x -> new TreeSet<>())
- );
- caughtUpClientsByTaskLoad.offerAll(asList(sourceClient, movement.destination));
- } else {
- // we found a candidate to trade standby/active state with our destination, so we don't need a warmup
- swapStandbyAndActive(
- movement.task,
- clientStates.get(standbySourceClient),
- clientStates.get(movement.destination)
- );
- caughtUpClientsByTaskLoad.offerAll(asList(standbySourceClient, movement.destination));
+ // Attempt to find a caught up standby, otherwise find any caught up client, failing that use the most
+ // caught up client.
+ final boolean moved = tryToSwapStandbyAndActiveOnCaughtUpClient(clientStates, caughtUpClientsByTaskLoad, movement) ||
+ tryToMoveActiveToCaughtUpClientAndTryToWarmUp(clientStates, warmups, remainingWarmupReplicas, caughtUpClientsByTaskLoad, movement) ||
+ tryToMoveActiveToMostCaughtUpClient(tasksToClientByLag, clientStates, warmups, remainingWarmupReplicas, caughtUpClientsByTaskLoad, movement);
Review comment:
Could you add tests to `TaskMovementTest` for case `tryToMoveActiveToMostCaughtUpClient()` that you added?
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