the-other-tim-brown commented on code in PR #17632: URL: https://github.com/apache/hudi/pull/17632#discussion_r2641654876
########## hudi-common/src/main/java/org/apache/hudi/common/util/HoodieArrowAllocator.java: ########## @@ -0,0 +1,85 @@ +/* + * 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.hudi.common.util; + +import org.apache.arrow.memory.BufferAllocator; +import org.apache.arrow.memory.RootAllocator; + +/** + * Manages Arrow BufferAllocator lifecycle for Arrow-based file format operations. + * + * <p>Following Arrow best practices: + * <ul> + * <li>Single RootAllocator per application</li> + * <li>Named child allocators for debugging and isolation</li> + * <li>Caller-specified memory limits per child allocator</li> + * </ul> + * + * <p>The root allocator is hardcoded to Long.MAX_VALUE and acts as a + * bookkeeper. Memory limits are enforced at the child allocator level, with each + * caller specifying an appropriate limit for their use case. + * + * @see <a href="https://arrow.apache.org/docs/java/memory.html";>Arrow Memory Management</a> + */ +public class HoodieArrowAllocator { + + private static volatile BufferAllocator rootAllocator; + + private HoodieArrowAllocator() { + // Utility class + } + + /** + * Get or create the shared root allocator using double-checked locking. Review Comment: You can avoid this locking by using the intialization-on-demand pattern https://en.wikipedia.org/wiki/Initialization-on-demand_holder_idiom ########## hudi-common/src/main/java/org/apache/hudi/common/util/HoodieArrowAllocator.java: ########## @@ -0,0 +1,85 @@ +/* + * 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.hudi.common.util; + +import org.apache.arrow.memory.BufferAllocator; +import org.apache.arrow.memory.RootAllocator; + +/** + * Manages Arrow BufferAllocator lifecycle for Arrow-based file format operations. + * + * <p>Following Arrow best practices: + * <ul> + * <li>Single RootAllocator per application</li> + * <li>Named child allocators for debugging and isolation</li> + * <li>Caller-specified memory limits per child allocator</li> + * </ul> + * + * <p>The root allocator is hardcoded to Long.MAX_VALUE and acts as a + * bookkeeper. Memory limits are enforced at the child allocator level, with each + * caller specifying an appropriate limit for their use case. + * + * @see <a href="https://arrow.apache.org/docs/java/memory.html";>Arrow Memory Management</a> + */ +public class HoodieArrowAllocator { + + private static volatile BufferAllocator rootAllocator; + + private HoodieArrowAllocator() { + // Utility class + } + + /** + * Get or create the shared root allocator using double-checked locking. + * The root allocator is (Long.MAX_VALUE). + */ + private static BufferAllocator getRootAllocator() { + if (rootAllocator == null) { + synchronized (HoodieArrowAllocator.class) { + if (rootAllocator == null) { + rootAllocator = new RootAllocator(Long.MAX_VALUE); + } + } + } + return rootAllocator; + } + + /** + * Create a named child allocator for Arrow operations. + * Caller is responsible for closing the returned allocator. + * + * @param name Descriptive name for debugging (e.g., "HoodieSparkLanceReader-data-file.lance") + * @param childSizeBytes Maximum memory size in bytes for this child allocator + * @return A new child allocator with the specified size limit + */ + public static BufferAllocator newChildAllocator(String name, long childSizeBytes) { + return getRootAllocator().newChildAllocator("hudi-arrow-" + name, 0, childSizeBytes); + } + + /** + * Close the root allocator. Should only be called during application shutdown Review Comment: Does this require a shutdown hook? -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
