[GitHub] [arrow] emkornfield commented on a change in pull request #7326: ARROW-9010: [Java] Framework and interface changes for RecordBatch IPC buffer compression

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emkornfield commented on a change in pull request #7326:
URL: https://github.com/apache/arrow/pull/7326#discussion_r480704140



##########
File path: java/vector/src/main/java/org/apache/arrow/vector/compression/CompressionCodec.java
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@@ -0,0 +1,51 @@
+/*
+ * 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.arrow.vector.compression;
+
+import org.apache.arrow.memory.ArrowBuf;
+import org.apache.arrow.memory.BufferAllocator;
+
+/**
+ * The codec for compression/decompression.
+ */
+public interface CompressionCodec {
+
+  /**
+   * Compress a buffer.
+   * @param allocator the allocator for allocating memory for compressed buffer.
+   * @param unCompressedBuffer the buffer to compress.
+   *                           Implementation of this method should take care of releasing this buffer.
+   * @return the compressed buffer.
+   */
+  ArrowBuf compress(BufferAllocator allocator, ArrowBuf unCompressedBuffer);

Review comment:
       @liyafan82 good points.  I think the other use-case I didn't consider is Flight which I think will already be in off-heap memory. 
   
   In terms of copies, the should be smaller in general, but it would be good to to understand if there are any limitations.  It looks like at least [airlift supports off-heap decompression](https://github.com/airlift/aircompressor/blob/master/src/main/java/io/airlift/compress/lz4/Lz4RawDecompressor.java), so I think this API is probably OK from that perspective.
   
   @rymurr did you have any other comments otherwise I can take another look and then I think we can merge.




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