JingsongLi commented on a change in pull request #7906: [FLINK-11830][table-planner-blink] Introduce CodeGeneratorContext to maintain reusable statements URL: https://github.com/apache/flink/pull/7906#discussion_r262784143
########## File path: flink-table/flink-table-runtime-blink/src/main/java/org/apache/flink/table/generated/CompileUtils.java ########## @@ -0,0 +1,89 @@ +/* + * 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.table.generated; + +import org.apache.flink.api.common.InvalidProgramException; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.shaded.guava18.com.google.common.cache.Cache; +import org.apache.flink.shaded.guava18.com.google.common.cache.CacheBuilder; +import org.codehaus.janino.SimpleCompiler; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * Utilities to compile a generated code to a Class. + */ +public final class CompileUtils { + + // used for logging the generated codes to a same place + private static Logger CODE_LOG = LoggerFactory.getLogger(CompileUtils.class); + + /** + * Cache of compile, Janino generates a new Class Loader and a new Class file every compile + * (guaranteeing that the class name will not be repeated). This leads to multiple tasks of + * the same process that generate a large number of duplicate class, resulting in a large + * number of Meta zone GC (class unloading), resulting in performance bottlenecks. So we add + * a cache to avoid this problem. + */ + protected static Cache<Tuple2<ClassLoader, String>, Class<?>> compileCache = CacheBuilder + .newBuilder() + .maximumSize(100) // estimated cache size + .build(); + + /** + * Compiles a generated code to a Class. + * @param cl the ClassLoader used to load the class + * @param name the class name + * @param code the generated code + * @param <T> the class type + * @return the compiled class + */ + public static <T> Class<T> compile(ClassLoader cl, String name, String code) { + Tuple2<ClassLoader, String> cacheKey = Tuple2.of(cl, name); + Class<?> clazz = compileCache.getIfPresent(cacheKey); + if (clazz == null) { + clazz = doCompile(cl, name, code); + compileCache.put(cacheKey, clazz); + } + //noinspection unchecked + return (Class<T>) clazz; + } + + private static <T> Class<T> doCompile(ClassLoader cl, String name, String code) { + checkNotNull(cl, "Classloader must not be null."); + CODE_LOG.debug("Compiling: %s \n\n Code:\n%s", name, code); + SimpleCompiler compiler = new SimpleCompiler(); + compiler.setParentClassLoader(cl); + try { + compiler.cook(code); + } catch (Throwable t) { + // TODO: println pretty code Review comment: I don't think println pretty code is a good idea, because it doesn't match the number of lines compiled incorrectly. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
