ableegoldman commented on a change in pull request #8497:
URL: https://github.com/apache/kafka/pull/8497#discussion_r411815724
##########
File path:
streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/TaskMovement.java
##########
@@ -16,128 +16,94 @@
*/
package org.apache.kafka.streams.processor.internals.assignment;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.LinkedList;
+import static
org.apache.kafka.streams.processor.internals.assignment.AssignmentUtils.taskIsCaughtUpOnClient;
+
import java.util.List;
import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
import java.util.SortedSet;
+import java.util.TreeSet;
import java.util.UUID;
import org.apache.kafka.streams.processor.TaskId;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
public class TaskMovement {
- private static final Logger log =
LoggerFactory.getLogger(TaskMovement.class);
-
final TaskId task;
- final UUID source;
- final UUID destination;
+ private final UUID destination;
- TaskMovement(final TaskId task, final UUID source, final UUID destination)
{
+ TaskMovement(final TaskId task, final UUID destination) {
this.task = task;
- this.source = source;
this.destination = destination;
}
- @Override
- public boolean equals(final Object o) {
- if (this == o) {
- return true;
- }
- if (o == null || getClass() != o.getClass()) {
- return false;
- }
- final TaskMovement movement = (TaskMovement) o;
- return Objects.equals(task, movement.task) &&
- Objects.equals(source, movement.source) &&
- Objects.equals(destination, movement.destination);
- }
-
- @Override
- public int hashCode() {
- return Objects.hash(task, source, destination);
- }
-
/**
- * Computes the movement of tasks from the state constrained to the
balanced assignment, up to the configured
- * {@code max.warmup.replicas}. A movement corresponds to a warmup replica
on the destination client, with
- * a few exceptional cases:
- * <p>
- * 1. Tasks whose destination clients are caught-up, or whose source
clients are not caught-up, will be moved
- * immediately from the source to the destination in the state constrained
assignment
- * 2. Tasks whose destination client previously had this task as a standby
will not be counted towards the total
- * {@code max.warmup.replicas}. Instead they will be counted against that
task's total {@code num.standby.replicas}.
- *
- * @param statefulActiveTaskAssignment the initial, state constrained
assignment, with the source clients
- * @param balancedStatefulActiveTaskAssignment the final, balanced
assignment, with the destination clients
- * @return list of the task movements from statefulActiveTaskAssignment to
balancedStatefulActiveTaskAssignment
+ * @return whether any warmup replicas were assigned
*/
- static List<TaskMovement> getMovements(final Map<UUID, List<TaskId>>
statefulActiveTaskAssignment,
- final Map<UUID, List<TaskId>>
balancedStatefulActiveTaskAssignment,
- final Map<TaskId, SortedSet<UUID>>
tasksToCaughtUpClients,
- final Map<UUID, ClientState>
clientStates,
- final Map<TaskId, Integer>
tasksToRemainingStandbys,
- final int maxWarmupReplicas) {
- if (statefulActiveTaskAssignment.size() !=
balancedStatefulActiveTaskAssignment.size()) {
- throw new IllegalStateException("Tried to compute movements but
assignments differ in size.");
- }
+ static boolean assignTaskMovements(final Map<UUID, List<TaskId>>
statefulActiveTaskAssignment,
+ final Map<TaskId, SortedSet<UUID>>
tasksToCaughtUpClients,
+ final Map<UUID, ClientState>
clientStates,
+ final Map<TaskId, Integer>
tasksToRemainingStandbys,
+ final int maxWarmupReplicas) {
+ boolean warmupReplicasAssigned = false;
+
+ final ValidClientsByTaskLoadQueue clientsByTaskLoad =
+ new ValidClientsByTaskLoadQueue(
+ clientStates,
+ (client, task) -> taskIsCaughtUpOnClient(task, client,
tasksToCaughtUpClients)
+ );
- final Map<TaskId, UUID> taskToDestinationClient = new HashMap<>();
- for (final Map.Entry<UUID, List<TaskId>> clientEntry :
balancedStatefulActiveTaskAssignment.entrySet()) {
- final UUID destination = clientEntry.getKey();
- for (final TaskId task : clientEntry.getValue()) {
- taskToDestinationClient.put(task, destination);
+ final SortedSet<TaskMovement> taskMovements = new TreeSet<>(
+ (movement, other) -> {
+ final int numCaughtUpClients =
tasksToCaughtUpClients.get(movement.task).size();
Review comment:
I think we've hit the same source of confusion as in the other thread.
But anything in `taskMovements`, and in fact any task that has an associated
`TaskMovement` object _must_ have at least one caught-up client. If it didn't,
we wouldn't be creating a warmup task for it; that's just a normal standby. A
warmup replica always implies there is an active version elsewhere on a
caught-up client
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
