[FLINK-10566] Fix exponential planning time of large programs

The traversal of the DAG is not efficient enough at some places which can lead
to very long plan creation times.

This introduces caching for the traversal to avoid traversing nodes multiple
times. Caching is performed at two places:

- when registering Kryo types
- when determining the maximum parallelism

flink-core/src/main/java/org/apache/flink/api/common/Plan.java

@@ -23,6 +23,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map.Entry;
 import java.util.Set;
@@ -361,10 +362,14 @@ public int getMaximumParallelism() {
 
  private static final class MaxDopVisitor implements Visitor<Operator<?>> {
 
+ private final Set<Operator> visitedOperators = new HashSet<>();
  private int maxDop = -1;
- 
+
  @Override
  public boolean preVisit(Operator<?> visitable) {
+ if (!visitedOperators.add(visitable)) {
+ return false;
+ }
  this.maxDop = Math.max(this.maxDop, visitable.getParallelism());
  return true;
  }

flink-java/src/main/java/org/apache/flink/api/java/ExecutionEnvironment.java

@@ -73,6 +73,7 @@
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Set;
 
 import static org.apache.flink.util.Preconditions.checkNotNull;
 
@@ -963,12 +964,16 @@ public Plan createProgramPlan(String jobName, boolean clearSinks) {
  if (!config.isAutoTypeRegistrationDisabled()) {
  plan.accept(new Visitor<org.apache.flink.api.common.operators.Operator<?>>() {
 
- private final HashSet<Class<?>> deduplicator = new HashSet<>();
+ private final Set<Class<?>> registeredTypes = new HashSet<>();
+ private final Set<org.apache.flink.api.common.operators.Operator<?>> visitedOperators = new HashSet<>();
 
  @Override
  public boolean preVisit(org.apache.flink.api.common.operators.Operator<?> visitable) {
+ if (!visitedOperators.add(visitable)) {
+ return false;
+ }
  OperatorInformation<?> opInfo = visitable.getOperatorInfo();
- Serializers.recursivelyRegisterType(opInfo.getOutputType(), config, deduplicator);
+ Serializers.recursivelyRegisterType(opInfo.getOutputType(), config, registeredTypes);
  return true;
  }
 

flink-tests/src/test/java/org/apache/flink/test/planning/LargePlanTest.java

@@ -0,0 +1,81 @@
+/*
+ * 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:https://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.test.planning;
+
+import org.apache.flink.api.common.functions.RichMapFunction;
+import org.apache.flink.api.common.typeinfo.Types;
+import org.apache.flink.api.java.DataSet;
+import org.apache.flink.api.java.ExecutionEnvironment;
+import org.apache.flink.api.java.io.DiscardingOutputFormat;
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.client.program.OptimizerPlanEnvironment;
+import org.apache.flink.client.program.PreviewPlanEnvironment;
+
+import org.junit.Test;
+
+/**
+ * Tests that large programs can be compiled to a Plan in reasonable amount of time.
+ */
+public class LargePlanTest {
+
+ @Test(expected = OptimizerPlanEnvironment.ProgramAbortException.class, timeout = 15_000)
+ public void testPlanningOfLargePlan() throws Exception {
+ runProgram(new PreviewPlanEnvironment(), 10, 50);
+ }
+
+ private static void runProgram(ExecutionEnvironment env, int depth, int width) throws Exception {
+ DataSet<String> input = env.fromElements("a", "b", "c");
+ DataSet<String> stats = null;
+
+ for (int i = 0; i < depth; i++) {
+ stats = analyze(input, stats, width / (i + 1) + 1);
+ }
+
+ stats.output(new DiscardingOutputFormat<>());
+ env.execute("depth " + depth + " width " + width);
+ }
+
+ private static DataSet<String> analyze(DataSet<String> input, DataSet<String> stats, int branches) {
+ for (int i = 0; i < branches; i++) {
+ final int ii = i;
+
+ if (stats != null) {
+ input = input.map(
+ new RichMapFunction<String, String>() {
+ @Override
+ public String map(String value) {
+ return value;
+ }
+ }).withBroadcastSet(stats.map(s -> "(" + s + ").map"), "stats");
+ }
+
+ DataSet<String> branch = input
+ .map(s -> new Tuple2<>(0, s + ii)).returns(Types.TUPLE(Types.STRING, Types.INT))
+ .groupBy(0)
+ .minBy(1)
+ .map(kv -> kv.f1).returns(Types.STRING);
+ if (stats == null) {
+ stats = branch;
+ } else {
+ stats = stats.union(branch);
+ }
+ }
+ return stats.map(s -> "(" + s + ").stats");
+ }
+}