Github user StephanEwen commented on a diff in the pull request:
https://github.com/apache/flink/pull/896#discussion_r34662347
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/accumulators/AccumulatorRegistry.java
---
@@ -0,0 +1,144 @@
+/*
+ * 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.accumulators;
+
+import org.apache.flink.api.common.JobID;
+import org.apache.flink.api.common.accumulators.Accumulator;
+import org.apache.flink.api.common.accumulators.LongCounter;
+import org.apache.flink.runtime.executiongraph.ExecutionAttemptID;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+
+/**
+ * Main accumulator registry which encapsulates internal and user-defined
accumulators.
+ */
+public class AccumulatorRegistry {
+
+ protected static final Logger LOG =
LoggerFactory.getLogger(AccumulatorRegistry.class);
+
+ protected final JobID jobID;
+ protected final ExecutionAttemptID taskID;
+
+ /* Flink's internal Accumulator values stored for the executing task. */
+ private final Map<Metric, Accumulator<?, ?>> flinkAccumulators =
+ new HashMap<Metric, Accumulator<?, ?>>();
+
+ /* User-defined Accumulator values stored for the executing task. */
+ private final Map<String, Accumulator<?, ?>> userAccumulators =
+ Collections.synchronizedMap(new HashMap<String,
Accumulator<?, ?>>());
+
+ /* The reporter returned to reporting tasks. */
+ private final ReadWriteReporter reporter;
+
+ /**
+ * Flink metrics supported
+ */
+ public enum Metric {
+ NUM_RECORDS_IN,
+ NUM_RECORDS_OUT,
+ NUM_BYTES_IN,
+ NUM_BYTES_OUT
+ }
+
+
+ public AccumulatorRegistry(JobID jobID, ExecutionAttemptID taskID) {
+ this.jobID = jobID;
+ this.taskID = taskID;
+ this.reporter = new ReadWriteReporter(flinkAccumulators);
+ }
+
+ /**
+ * Creates a snapshot of this accumulator registry.
+ * @return a serialized accumulator map
+ */
+ public AccumulatorSnapshot getSnapshot() {
+ try {
+ return new AccumulatorSnapshot(jobID, taskID,
flinkAccumulators, userAccumulators);
+ } catch (IOException e) {
+ LOG.warn("Failed to serialize accumulators for task.",
e);
+ return null;
+ }
+ }
+
+ /**
+ * Gets the map for user-defined accumulators.
+ */
+ public Map<String, Accumulator<?, ?>> getUserMap() {
+ return userAccumulators;
+ }
+
+ /**
+ * Gets the reporter for flink internal metrics.
+ */
+ public Reporter getReadWriteReporter() {
+ return reporter;
+ }
+
+ /**
+ * Interface for Flink's internal accumulators.
+ */
+ public interface Reporter {
+ void report(Metric metric, long value);
+ }
+
+ /**
+ * Accumulator based reporter for keeping track of internal metrics
(e.g. bytes and records in/out)
+ */
+ public static class ReadWriteReporter implements Reporter {
+
+ private LongCounter numRecordsIn = new LongCounter();
+ private LongCounter numRecordsOut = new LongCounter();
+ private LongCounter numBytesIn = new LongCounter();
+ private LongCounter numBytesOut = new LongCounter();
+
+ public ReadWriteReporter(Map<Metric, Accumulator<?,?>>
accumulatorMap) {
+ accumulatorMap.put(Metric.NUM_RECORDS_IN, numRecordsIn);
+ accumulatorMap.put(Metric.NUM_RECORDS_OUT,
numRecordsOut);
+ accumulatorMap.put(Metric.NUM_BYTES_IN, numBytesIn);
+ accumulatorMap.put(Metric.NUM_BYTES_OUT, numBytesOut);
+ }
+
+ @Override
+ public void report(Metric metric, long value) {
--- End diff --
This is called extremely often - once per tuple. It needs to have virtually
zero overhead.
To achieve that, I would add dedicated methods for each metric, rather than
have the enumeration.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
