Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3511#discussion_r139926078
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/codegeneration/SorterFactory.java
---
@@ -0,0 +1,174 @@
+/*
+ * 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.codegeneration;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeutils.TypeComparator;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.core.memory.MemorySegment;
+import org.apache.flink.runtime.operators.sort.FixedLengthRecordSorter;
+import org.apache.flink.runtime.operators.sort.InMemorySorter;
+import org.apache.flink.runtime.operators.sort.NormalizedKeySorter;
+
+import freemarker.template.TemplateException;
+
+import org.codehaus.commons.compiler.CompileException;
+import org.codehaus.janino.SimpleCompiler;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.HashMap;
+import java.util.List;
+
+/**
+ * {@link SorterFactory} is a singleton class that provides
functionalities to create the most suitable sorter
+ * for underlying data based on {@link TypeComparator}.
+ * Note: the generated code can be inspected by configuring Janino to
write the code that is being compiled
+ * to a file, see http://janino-compiler.github.io/janino/#debugging
+ */
+public class SorterFactory {
+ //
------------------------------------------------------------------------
+ // Constants
+ //
------------------------------------------------------------------------
+ private static final Logger LOG =
LoggerFactory.getLogger(SorterFactory.class);
+
+ /** Fixed length records with a length below this threshold will be
in-place sorted, if possible. */
+ private static final int THRESHOLD_FOR_IN_PLACE_SORTING = 32;
+
+ //
------------------------------------------------------------------------
+ // Singleton Attribute
+ //
------------------------------------------------------------------------
+ private static SorterFactory sorterFactory;
+
+ //
------------------------------------------------------------------------
+ // Attributes
+ //
------------------------------------------------------------------------
+ private SimpleCompiler classCompiler;
+ private TemplateManager templateManager;
+ private HashMap<String, Constructor> constructorCache;
+
+ /**
+ * This is only for testing. If an error occurs, we want to fail the
test, instead of falling back
+ * to a non-generated sorter.
+ */
+ public boolean forceCodeGeneration = false;
+
+ /**
+ * Constructor.
+ */
+ private SorterFactory() {
+ this.templateManager = TemplateManager.getInstance();
+ this.classCompiler = new SimpleCompiler();
+ this.constructorCache = new HashMap<>();
+ }
+
+ /**
+ * A method to get a singleton instance
+ * or create one if it hasn't been created yet.
+ * @return
+ */
+ public static synchronized SorterFactory getInstance() {
+ if (sorterFactory == null){
+ sorterFactory = new SorterFactory();
+ }
+
+ return sorterFactory;
+ }
+
+
+ /**
+ * Create a sorter for the given type comparator and
+ * assign serializer, comparator and memory to the sorter.
+ * @param serializer
+ * @param comparator
+ * @param memory
+ * @return
+ */
+ public <T> InMemorySorter<T> createSorter(ExecutionConfig config,
TypeSerializer<T> serializer, TypeComparator<T> comparator, List<MemorySegment>
memory) {
+ if (config.isCodeGenerationForSorterEnabled()){
+ try {
+ return createCodegenSorter(serializer,
comparator, memory);
+ } catch (IOException | TemplateException |
ClassNotFoundException | IllegalAccessException |
+ InstantiationException |
NoSuchMethodException | InvocationTargetException | CompileException e) {
+ String msg = "Serializer: " + serializer +
+ "[" + serializer + "],
comparator: [" + comparator + "], exception: " + e.toString();
+ if (!forceCodeGeneration) {
+ LOG.warn("An error occurred while
trying to create a code generated sorter. Using non-codegen sorter instead. " +
msg);
+ return
createNonCodegenSorter(serializer, comparator, memory);
+ } else {
+ throw new RuntimeException("An error
occurred while trying to create a code generated sorter. Failing the job,
because forceCodeGeneration. " + msg);
+ }
+ }
+ } else {
+ return createNonCodegenSorter(serializer, comparator,
memory);
+ }
+ }
+
+ private <T> InMemorySorter<T> createCodegenSorter(TypeSerializer<T>
serializer, TypeComparator<T> comparator, List<MemorySegment> memory)
+ throws IOException, TemplateException,
ClassNotFoundException, IllegalAccessException, InstantiationException,
NoSuchMethodException, InvocationTargetException, CompileException {
+ SorterTemplateModel sorterModel = new
SorterTemplateModel(comparator);
+
+ Constructor sorterConstructor;
+
+ synchronized (this){
+ if
(constructorCache.getOrDefault(sorterModel.getSorterName(), null) != null) {
--- End diff --
`constructorCache.containsKey(sorterModel.getSorterName())`?
---
