[GitHub] [parquet-mr] gszadovszky commented on a change in pull request #793: PARQUET-1866: Replace Hadoop ZSTD with JNI-ZSTD

[GitBox <gi...@apache.org>]

gszadovszky commented on a change in pull request #793:
URL: https://github.com/apache/parquet-mr/pull/793#discussion_r433675252



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File path: parquet-hadoop/src/test/java/org/apache/parquet/hadoop/TestZstandardCodec.java
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@@ -0,0 +1,146 @@
+/* 
+ * 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.hadoop;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.io.compress.CompressionOutputStream;
+import org.apache.hadoop.mapred.JobClient;
+import org.apache.hadoop.mapred.JobConf;
+import org.apache.hadoop.mapred.OutputCollector;
+import org.apache.hadoop.mapred.Reporter;
+import org.apache.hadoop.mapred.RunningJob;
+import org.apache.hadoop.mapred.TextInputFormat;
+import org.apache.parquet.bytes.BytesInput;
+import org.apache.parquet.example.data.Group;
+import org.apache.parquet.example.data.simple.SimpleGroupFactory;
+import org.apache.parquet.hadoop.codec.ZstandardCodec;
+import org.apache.parquet.hadoop.example.GroupWriteSupport;
+import org.apache.parquet.hadoop.mapred.DeprecatedParquetOutputFormat;
+import org.apache.parquet.hadoop.metadata.CompressionCodecName;
+import org.apache.parquet.schema.MessageTypeParser;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.util.Random;
+
+public class TestZstandardCodec {
+
+  private final Path inputPath = new Path("src/test/java/org/apache/parquet/hadoop/example/TestInputOutputFormat.java");
+
+  @Test
+  public void testZstdCodec() throws IOException {
+    ZstandardCodec codec = new ZstandardCodec();
+    Configuration conf = new Configuration();
+    int[] levels = {1, 4, 7, 10, 13, 16, 19, 22};
+    int[] dataSizes = {0, 1, 10, 1024, 1024 * 1024};
+
+    for (int i = 0; i < levels.length; i++) {
+      conf.setInt(ZstandardCodec.PARQUET_COMPRESS_ZSTD_LEVEL, levels[i]);
+      codec.setConf(conf);
+      for (int j = 0; j < dataSizes.length; j++) {
+        testZstd(codec, dataSizes[j]);
+      }
+    }
+  }
+
+  private void testZstd(ZstandardCodec codec, int dataSize) throws IOException {
+    byte[] data = new byte[dataSize];
+    (new Random()).nextBytes(data);
+    BytesInput compressedData = compress(codec,  BytesInput.from(data));
+    BytesInput decompressedData = decompress(codec, compressedData, data.length);
+    Assert.assertArrayEquals(data, decompressedData.toByteArray());
+  }
+
+  private BytesInput compress(ZstandardCodec codec, BytesInput bytes) throws IOException {
+    ByteArrayOutputStream compressedOutBuffer = new ByteArrayOutputStream((int)bytes.size());
+    CompressionOutputStream cos = codec.createOutputStream(compressedOutBuffer, null);
+    bytes.writeAllTo(cos);
+    cos.close();
+    return BytesInput.from(compressedOutBuffer);
+  }
+
+  private BytesInput decompress(ZstandardCodec codec, BytesInput bytes, int uncompressedSize) throws IOException {
+    BytesInput decompressed;
+    InputStream is = codec.createInputStream(bytes.toInputStream(), null);
+    decompressed = BytesInput.from(is, uncompressedSize);
+    is.close();
+    return decompressed;
+  }
+
+  @Test
+  public void testZstdConfWithMr() throws Exception {
+    JobConf jobConf = new JobConf();
+    Configuration conf = new Configuration();
+    jobConf.setInt(ZstandardCodec.PARQUET_COMPRESS_ZSTD_LEVEL, 18);
+    jobConf.setInt(ZstandardCodec.PARQUET_COMPRESS_ZSTD_LEVEL, 4);
+    RunningJob mapRedJob = runMapReduceJob(CompressionCodecName.ZSTD, jobConf, conf);
+    assert(mapRedJob.isSuccessful());
+  }
+
+  private RunningJob runMapReduceJob(CompressionCodecName codec, JobConf jobConf, Configuration conf) throws IOException, ClassNotFoundException, InterruptedException {

Review comment:
       Yes, I know, there is no 100% guarantee in normal circumstances. But if you write the test in a deterministic way (as it should be by e.g. using a fix seed for random generation) then without changing the data and the compression codec it shall be fine. I worth a comment, though about it is not the nicest way of testing the work of the properties but currently that's seems to be the only one.




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