pnowojski commented on a change in pull request #11899: URL: https://github.com/apache/flink/pull/11899#discussion_r419423753
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/CheckpointRequestDecider.java ########## @@ -0,0 +1,156 @@ +/* + * 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.flink.runtime.checkpoint; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.runtime.checkpoint.CheckpointCoordinator.CheckpointTriggerRequest; +import org.apache.flink.runtime.util.clock.Clock; + +import java.util.Optional; +import java.util.PriorityQueue; +import java.util.function.Consumer; +import java.util.function.Function; +import java.util.function.Supplier; + +import static org.apache.flink.runtime.checkpoint.CheckpointFailureReason.MINIMUM_TIME_BETWEEN_CHECKPOINTS; +import static org.apache.flink.runtime.checkpoint.CheckpointFailureReason.TOO_MANY_CONCURRENT_CHECKPOINTS; + +@SuppressWarnings("ConstantConditions") +class CheckpointRequestDecider { + private static final int MAX_QUEUED_REQUESTS = 1000; + + private final int maxConcurrentCheckpointAttempts; + private final Consumer<Long> rescheduleTrigger; + private final Clock clock; + private final long minPauseBetweenCheckpoints; + private final Supplier<Integer> pendingCheckpointsSizeSupplier; + private final Function<Supplier<Optional<CheckpointTriggerRequest>>, Optional<CheckpointTriggerRequest>> sync; + private final PriorityQueue<CheckpointTriggerRequest> triggerRequestQueue = new PriorityQueue<>((r1, r2) -> { + if (r1.props.isSavepoint() != r2.props.isSavepoint()) { + return r1.props.isSavepoint() ? -1 : 1; + } else if (r1.props.forceCheckpoint() != r2.props.forceCheckpoint()) { + return r1.props.forceCheckpoint() ? -1 : 1; + } else if (r1.isPeriodic != r2.isPeriodic) { + return r1.isPeriodic ? 1 : -1; + } else { + return Long.compare(r1.timestamp, r2.timestamp); + } + }); + + CheckpointRequestDecider( + int maxConcurrentCheckpointAttempts, + Consumer<Long> rescheduleTrigger, + Clock clock, + long minPauseBetweenCheckpoints, + Supplier<Integer> pendingCheckpointsSizeSupplier, + Function<Supplier<Optional<CheckpointTriggerRequest>>, + Optional<CheckpointTriggerRequest>> sync) { + this.maxConcurrentCheckpointAttempts = maxConcurrentCheckpointAttempts; + this.rescheduleTrigger = rescheduleTrigger; + this.clock = clock; + this.minPauseBetweenCheckpoints = minPauseBetweenCheckpoints; + this.pendingCheckpointsSizeSupplier = pendingCheckpointsSizeSupplier; + this.sync = sync; + } + + Optional<CheckpointTriggerRequest> chooseRequestToExecute(CheckpointTriggerRequest newRequest, boolean isTriggering, long lastCompletionMs) { + return chooseRequestToExecute(false, () -> newRequest, isTriggering, lastCompletionMs); + } + + Optional<CheckpointTriggerRequest> chooseQueuedRequestToExecute(boolean isTriggering, long lastCompletionMs) { + return chooseRequestToExecute(true, triggerRequestQueue::peek, isTriggering, lastCompletionMs); + } + + /** + * Choose the next {@link CheckpointTriggerRequest request} to execute based on the provided candidate and the + * current state. Acquires a lock and may update the state. + * @return request to execute, if any. + */ + private Optional<CheckpointTriggerRequest> chooseRequestToExecute( + boolean isEnqueued, + Supplier<CheckpointTriggerRequest> candidateSupplier, + boolean isTriggering, + long lastCompletionMs) { + return sync.apply(() -> { + final CheckpointTriggerRequest candidate = candidateSupplier.get(); + if (candidate == null) { + return Optional.empty(); + } else if (isTriggering) { + return onCantTriggerNow(candidate, isEnqueued); + } else if (pendingCheckpointsSizeSupplier.get() >= maxConcurrentCheckpointAttempts) { + return onCantCheckpointNow(candidate, TOO_MANY_CONCURRENT_CHECKPOINTS, () -> { /* not used */ }, isEnqueued); + } else if (nextTriggerDelayMillis(lastCompletionMs) > 0) { + return onCantCheckpointNow(candidate, MINIMUM_TIME_BETWEEN_CHECKPOINTS, () -> rescheduleTrigger.accept(nextTriggerDelayMillis(lastCompletionMs)), isEnqueued); + } else if (candidate != triggerRequestQueue.peek()) { + triggerRequestQueue.offer(candidate); + return Optional.of(triggerRequestQueue.poll()); + } else { + return Optional.of(isEnqueued ? triggerRequestQueue.poll() : candidate); + } + }); + } + + private Optional<CheckpointTriggerRequest> onCantTriggerNow(CheckpointTriggerRequest candidate, boolean isEnqueued) { + offerIfNeeded(candidate, isEnqueued); + return Optional.empty(); + } + + private Optional<CheckpointTriggerRequest> onCantCheckpointNow( + CheckpointTriggerRequest candidate, + CheckpointFailureReason dropReason, + Runnable postDrop, + boolean isEnqueued) { + if (candidate.props.forceCheckpoint()) { + return Optional.of(isEnqueued ? triggerRequestQueue.poll() : candidate); + } else if (candidate.isPeriodic) { + if (isEnqueued) { + triggerRequestQueue.poll(); + } + candidate.onCompletionPromise.completeExceptionally(new CheckpointException(dropReason)); + postDrop.run(); + } + offerIfNeeded(candidate, isEnqueued); + return Optional.empty(); + } + + private void offerIfNeeded(CheckpointTriggerRequest candidate, boolean isEnqueued) { + if (!isEnqueued) { + if (triggerRequestQueue.size() < MAX_QUEUED_REQUESTS) { + triggerRequestQueue.offer(candidate); + } else { + candidate.onCompletionPromise.completeExceptionally(new CheckpointException(CheckpointFailureReason.TOO_MANY_CHECKPOINT_REQUESTS)); Review comment: I would still add a test for that. It's a valid feature and handling the corner/error cases is an important thing. ---------------------------------------------------------------- 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
