lindong28 commented on code in PR #248: URL: https://github.com/apache/flink-ml/pull/248#discussion_r1299531846
########## flink-ml-iteration/flink-ml-iteration-common/src/main/java/org/apache/flink/iteration/operator/feedback/SpillableFeedbackQueue.java: ########## @@ -0,0 +1,115 @@ +/* + * 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.iteration.operator.feedback; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.core.memory.DataInputView; +import org.apache.flink.core.memory.DataOutputSerializer; +import org.apache.flink.core.memory.MemorySegment; +import org.apache.flink.runtime.io.disk.InputViewIterator; +import org.apache.flink.runtime.io.disk.SpillingBuffer; +import org.apache.flink.runtime.io.disk.iomanager.IOManager; +import org.apache.flink.runtime.memory.MemoryAllocationException; +import org.apache.flink.runtime.memory.MemoryManager; +import org.apache.flink.table.runtime.operators.sort.ListMemorySegmentPool; +import org.apache.flink.util.MutableObjectIterator; + +import java.io.IOException; +import java.util.List; +import java.util.Objects; + +/** + * * A queue that can spill the items to disks automatically when the memory buffer is full. + * + * @param <T> The element type. + */ +@Internal +final class SpillableFeedbackQueue<T> { + private final DataOutputSerializer output = new DataOutputSerializer(256); + private final TypeSerializer<T> serializer; + private final IOManager ioManager; + private final MemoryManager memoryManager; + private final int numPages; + + private List<MemorySegment> segments; + private ListMemorySegmentPool segmentPool; + + private SpillingBuffer target; + private long size = 0L; + + SpillableFeedbackQueue( + IOManager ioManager, + MemoryManager memoryManager, + TypeSerializer<T> serializer, + long inMemoryBufferSize, + long pageSize) + throws MemoryAllocationException { + this.serializer = Objects.requireNonNull(serializer); + this.ioManager = Objects.requireNonNull(ioManager); + this.memoryManager = Objects.requireNonNull(memoryManager); + + this.numPages = (int) (inMemoryBufferSize / pageSize); + resetSpillingBuffer(); + } + + void add(T item) { + try { + output.clear(); + serializer.serialize(item, output); + target.write(output.getSharedBuffer(), 0, output.length()); + size++; + } catch (IOException e) { + throw new IllegalStateException(e); + } + } + + MutableObjectIterator<T> iterate() { + try { + DataInputView input = target.flip(); + return new InputViewIterator<>(input, this.serializer); + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + long size() { + return size; + } + + void reset() throws Exception { + size = 0; + close(); + resetSpillingBuffer(); Review Comment: Just to summarize our offline discussions: - Currently MemoryManager#allocatePages will allocate memory from JVM rather than re-using allocated memory from a pool. We should avoid this repeated memory allocation. - AbstractPagedOutputView, the parent class of SpillingBuffer, provides clear() and advance() to support writing to a buffer after it has been read. It might be possible to let `SpillingBuffer` implement these two APIs so that we can re-use it for writing after it is read. - NormalizedKeySorter#reset supports re-using a buffer after it is read. -- 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: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
