cshuo commented on code in PR #19728: URL: https://github.com/apache/hudi/pull/19728#discussion_r3861505178
########## hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/buffer/PreemptiveMemorySegmentPool.java: ########## @@ -0,0 +1,126 @@ +/* + * 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.sink.buffer; + +import org.apache.hudi.common.util.ValidationUtils; + +import org.apache.flink.core.memory.MemorySegment; +import org.apache.flink.table.runtime.util.MemorySegmentPool; + +import javax.annotation.Nullable; + +import java.io.Closeable; +import java.io.IOException; +import java.util.List; + +/** + * A {@link MemorySegmentPool} wrapper that can reclaim pages from an inactive owner when the + * delegate pool is exhausted. + * + * <p>The owner represents the bucket whose buffer is currently requesting pages. The reclaimer + * must never reclaim that owner because the request may occur in the middle of serializing a row. + * If no other owner can release pages, this pool returns {@code null} and lets the caller handle + * the allocation failure. + */ +public class PreemptiveMemorySegmentPool implements MemorySegmentPool, Closeable { + + /** Callback that reclaims memory from an owner other than the excluded in-flight owner. */ + @FunctionalInterface + public interface MemoryReclaimer { + /** + * Reclaims memory from an inactive owner. + * + * @param excludedOwnerId the owner currently requesting a page + * @return {@code true} if memory was reclaimed and allocation should be retried + */ + boolean reclaim(String excludedOwnerId); + } + + private final MemorySegmentPool delegate; + private final MemoryReclaimer memoryReclaimer; + + @Nullable + private String currentOwnerId; + private boolean preempting; Review Comment: Is `preempting` flag necessary, Could you clarify the purpose of the flag or add some comments. ########## hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/buffer/PreemptiveMemorySegmentPool.java: ########## @@ -0,0 +1,126 @@ +/* + * 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.sink.buffer; + +import org.apache.hudi.common.util.ValidationUtils; + +import org.apache.flink.core.memory.MemorySegment; +import org.apache.flink.table.runtime.util.MemorySegmentPool; + +import javax.annotation.Nullable; + +import java.io.Closeable; +import java.io.IOException; +import java.util.List; + +/** + * A {@link MemorySegmentPool} wrapper that can reclaim pages from an inactive owner when the + * delegate pool is exhausted. + * + * <p>The owner represents the bucket whose buffer is currently requesting pages. The reclaimer + * must never reclaim that owner because the request may occur in the middle of serializing a row. + * If no other owner can release pages, this pool returns {@code null} and lets the caller handle + * the allocation failure. + */ +public class PreemptiveMemorySegmentPool implements MemorySegmentPool, Closeable { + + /** Callback that reclaims memory from an owner other than the excluded in-flight owner. */ + @FunctionalInterface + public interface MemoryReclaimer { + /** + * Reclaims memory from an inactive owner. + * + * @param excludedOwnerId the owner currently requesting a page + * @return {@code true} if memory was reclaimed and allocation should be retried + */ + boolean reclaim(String excludedOwnerId); + } + + private final MemorySegmentPool delegate; + private final MemoryReclaimer memoryReclaimer; + + @Nullable + private String currentOwnerId; + private boolean preempting; + + public PreemptiveMemorySegmentPool( + MemorySegmentPool delegate, + MemoryReclaimer memoryReclaimer) { + ValidationUtils.checkArgument(delegate != null, "Delegate memory segment pool must not be null"); + ValidationUtils.checkArgument(memoryReclaimer != null, "Memory reclaimer must not be null"); + this.delegate = delegate; + this.memoryReclaimer = memoryReclaimer; + } + + /** Marks the owner whose buffer is currently requesting memory pages. */ + public void setCurrentOwner(String ownerId) { + ValidationUtils.checkArgument(ownerId != null, "Memory segment pool owner must not be null"); + ValidationUtils.checkState( + currentOwnerId == null, + "A memory segment pool owner is already active: " + currentOwnerId); + this.currentOwnerId = ownerId; + } + + /** Clears the current owner after its buffer write finishes. */ + public void clearCurrentOwner() { + this.currentOwnerId = null; + } + + @Override + public int pageSize() { + return delegate.pageSize(); + } + + @Override + public void returnAll(List<MemorySegment> memorySegments) { + delegate.returnAll(memorySegments); + } + + @Override + public int freePages() { + return delegate.freePages(); + } + + @Override + public MemorySegment nextSegment() { + MemorySegment segment = delegate.nextSegment(); + if (segment != null || currentOwnerId == null || preempting) { Review Comment: Could you clarify when will `currentOwnerId` be null? ########## hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/StreamWriteFunction.java: ########## Review Comment: As discussed in https://github.com/apache/hudi/pull/19692#discussion_r3827189498, Now that memory exhaustion during `writeRow()` already triggers `MemoryReclaimer#reclaim` to flush the largest inactive bucket, we don't need to eagerly flush `bucketToFlush` when failedBucket is diverged? ########## hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/StreamWriteFunction.java: ########## @@ -149,6 +150,8 @@ public class StreamWriteFunction extends AbstractStreamWriteFunction<HoodieFlink protected transient MemorySegmentPool memorySegmentPool; Review Comment: Do we still need to keep `memorySegmentPool`, seems we can use `preemptiveMemorySegmentPool` throughout. -- This is an automated message from the Apache Git Service. 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