org.apache.flink.runtime.rest.handler.job.checkpoints.CheckpointStatsCache Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.runtime.rest.handler.job.checkpoints;
import org.apache.flink.runtime.checkpoint.AbstractCheckpointStats;
import org.apache.flink.shaded.guava18.com.google.common.cache.Cache;
import org.apache.flink.shaded.guava18.com.google.common.cache.CacheBuilder;
import javax.annotation.Nullable;
/**
* A size-based cache of accessed checkpoints for completed and failed
* checkpoints.
*
* Having this cache in place for accessed stats improves the user
* experience quite a bit as accessed checkpoint stats stay available
* and don't expire. For example if you manage to click on the last
* checkpoint in the history, it is not available via the stats as soon
* as another checkpoint is triggered. With the cache in place, the
* checkpoint will still be available for investigation.
*/
public class CheckpointStatsCache {
@Nullable
private final Cache cache;
public CheckpointStatsCache(int maxNumEntries) {
if (maxNumEntries > 0) {
this.cache = CacheBuilder.newBuilder()
.maximumSize(maxNumEntries)
.build();
} else {
this.cache = null;
}
}
/**
* Try to add the checkpoint to the cache.
*
* @param checkpoint Checkpoint to be added.
*/
public void tryAdd(AbstractCheckpointStats checkpoint) {
// Don't add in progress checkpoints as they will be replaced by their
// completed/failed version eventually.
if (cache != null && checkpoint != null && !checkpoint.getStatus().isInProgress()) {
cache.put(checkpoint.getCheckpointId(), checkpoint);
}
}
/**
* Try to look up a checkpoint by it's ID in the cache.
*
* @param checkpointId ID of the checkpoint to look up.
* @return The checkpoint or null if checkpoint not found.
*/
public AbstractCheckpointStats tryGet(long checkpointId) {
if (cache != null) {
return cache.getIfPresent(checkpointId);
} else {
return null;
}
}
}