Github user heytitle commented on a diff in the pull request:
https://github.com/apache/flink/pull/3511#discussion_r140662538
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/codegeneration/SorterFactory.java
---
@@ -0,0 +1,198 @@
+/*
+ * 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.Configuration;
+import freemarker.template.Template;
+import freemarker.template.TemplateException;
+import freemarker.template.TemplateExceptionHandler;
+import freemarker.template.Version;
+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.io.StringWriter;
+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 HashMap<String, Constructor> constructorCache;
+ private final Template template;
+
+ /**
+ * 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.classCompiler = new SimpleCompiler();
+
this.classCompiler.setParentClassLoader(this.getClass().getClassLoader());
--- End diff --
Thanks for the comment. I have a further comment on this
What I understand is that If `SorterFactory` is a singleton object and its
parent class loader isn't the user one, it might happen that the next job will
fail to create new code-generated sorters. This is due to the fact that
`classComplier` is removed after the first job finishes and it is instantiated
only once when `SorterFactory is created.
Please correct me if I'm wrong.
---
