Add JMH CompressionBenchmark for isolated codec throughput measurement

Benchmarks raw compress/decompress throughput for each supported codec
(SNAPPY, ZSTD, LZ4_RAW, GZIP) at page sizes 8KB, 64KB, and 256KB using
the heap-based CodecFactory path. Input data mixes sequential, repeated,
low-range random, and full random patterns for realistic compression ratios.

Author: iemejia

parquet-benchmarks/src/main/java/org/apache/parquet/benchmarks/CompressionBenchmark.java

@@ -0,0 +1,153 @@
+/*
+ * 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.parquet.benchmarks;
+
+import java.io.IOException;
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.parquet.bytes.BytesInput;
+import org.apache.parquet.compression.CompressionCodecFactory;
+import org.apache.parquet.hadoop.CodecFactory;
+import org.apache.parquet.hadoop.metadata.CompressionCodecName;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.TearDown;
+import org.openjdk.jmh.annotations.Warmup;
+
+/**
+ * Isolated JMH benchmarks for raw Parquet compression and decompression throughput.
+ *
+ * <p>Measures the performance of {@link CompressionCodecFactory.BytesInputCompressor}
+ * and {@link CompressionCodecFactory.BytesInputDecompressor} for each supported codec,
+ * using the heap-based {@link CodecFactory} path. Input data is generated to approximate
+ * realistic Parquet page content (a mix of sequential, repeated, and random byte patterns).
+ *
+ * <p>This benchmark isolates the codec hot path from file I/O, encoding, and other
+ * Parquet overhead, making it ideal for measuring compression-specific optimizations.
+ */
+@BenchmarkMode(Mode.Throughput)
+@OutputTimeUnit(TimeUnit.SECONDS)
+@Fork(1)
+@Warmup(iterations = 3, time = 2)
+@Measurement(iterations = 5, time = 3)
+@State(Scope.Thread)
+public class CompressionBenchmark {
+
+  @Param({"SNAPPY", "ZSTD", "LZ4_RAW", "GZIP"})
+  public String codec;
+
+  @Param({"8192", "65536", "262144"})
+  public int pageSize;
+
+  private byte[] uncompressedData;
+  private byte[] compressedData;
+  private int decompressedSize;
+
+  private CompressionCodecFactory.BytesInputCompressor compressor;
+  private CompressionCodecFactory.BytesInputDecompressor decompressor;
+  private CodecFactory factory;
+
+  @Setup(Level.Trial)
+  public void setup() throws IOException {
+    uncompressedData = generatePageData(pageSize, 42L);
+    decompressedSize = uncompressedData.length;
+
+    Configuration conf = new Configuration();
+    factory = new CodecFactory(conf, pageSize);
+    CompressionCodecName codecName = CompressionCodecName.valueOf(codec);
+
+    compressor = factory.getCompressor(codecName);
+    decompressor = factory.getDecompressor(codecName);
+
+    // Pre-compress for decompression benchmark; copy to a stable byte array
+    // since the compressor may reuse its internal buffer.
+    BytesInput compressed = compressor.compress(BytesInput.from(uncompressedData));
+    compressedData = compressed.toByteArray();
+  }
+
+  @TearDown(Level.Trial)
+  public void tearDown() {
+    factory.release();
+  }
+
+  @Benchmark
+  public BytesInput compress() throws IOException {
+    return compressor.compress(BytesInput.from(uncompressedData));
+  }
+
+  @Benchmark
+  public byte[] decompress() throws IOException {
+    // Force materialization of the decompressed data. Without this, codecs using
+    // the stream-based HeapBytesDecompressor (e.g. GZIP) would return a lazy
+    // StreamBytesInput, deferring the actual work. toByteArray() is essentially
+    // free for our optimized implementations (returns the existing byte[]).
+    return decompressor.decompress(BytesInput.from(compressedData), decompressedSize).toByteArray();
+  }
+
+  /**
+   * Generates byte data that approximates realistic Parquet page content.
+   * Mixes sequential runs, repeated values, low-range random, and full random
+   * to produce a realistic compression ratio (~2-4x for fast codecs).
+   */
+  static byte[] generatePageData(int size, long seed) {
+    Random random = new Random(seed);
+    byte[] data = new byte[size];
+    int i = 0;
+    while (i < size) {
+      int patternType = random.nextInt(4);
+      int chunkSize = Math.min(random.nextInt(256) + 64, size - i);
+      switch (patternType) {
+        case 0: // Sequential bytes (highly compressible)
+          for (int j = 0; j < chunkSize && i < size; j++) {
+            data[i++] = (byte) (j & 0xFF);
+          }
+          break;
+        case 1: // Repeated value (highly compressible)
+          byte val = (byte) random.nextInt(256);
+          for (int j = 0; j < chunkSize && i < size; j++) {
+            data[i++] = val;
+          }
+          break;
+        case 2: // Small range random (moderately compressible)
+          for (int j = 0; j < chunkSize && i < size; j++) {
+            data[i++] = (byte) random.nextInt(16);
+          }
+          break;
+        case 3: // Full random (low compressibility)
+          byte[] randomChunk = new byte[chunkSize];
+          random.nextBytes(randomChunk);
+          int toCopy = Math.min(chunkSize, size - i);
+          System.arraycopy(randomChunk, 0, data, i, toCopy);
+          i += toCopy;
+          break;
+      }
+    }
+    return data;
+  }
+}