[SPARK-26509][SQL] Parquet DELTA_BYTE_ARRAY is not supported in Spark 2.x's Vectorized Reader

sql/core/src/main/java/org/apache/spark/sql/execution/datasources/parquet/VectorizedColumnReader.java

@@ -580,10 +580,7 @@ private void initDataReader(Encoding dataEncoding, ByteBufferInputStream in) thr
       this.dataColumn = new VectorizedRleValuesReader();
       this.isCurrentPageDictionaryEncoded = true;
     } else {
-      if (dataEncoding != Encoding.PLAIN) {
-        throw new UnsupportedOperationException("Unsupported encoding: " + dataEncoding);
-      }
-      this.dataColumn = new VectorizedPlainValuesReader();
+      this.dataColumn = getValuesReader(dataEncoding);
       this.isCurrentPageDictionaryEncoded = false;
     }
 
@@ -594,6 +591,19 @@ private void initDataReader(Encoding dataEncoding, ByteBufferInputStream in) thr
     }
   }
 
+  private ValuesReader getValuesReader(Encoding encoding) {
+    switch (encoding) {
+      case PLAIN:
+        return new VectorizedPlainValuesReader();
+      case DELTA_BYTE_ARRAY:
+        return new VectorizedDeltaByteArrayReader();
+      case DELTA_BINARY_PACKED:
+        return new VectorizedDeltaBinaryPackedReader();
+      default:
+        throw new UnsupportedOperationException("Unsupported encoding: " + encoding);
+    }
+  }
+
   private void readPageV1(DataPageV1 page) throws IOException {
     this.pageValueCount = page.getValueCount();
     ValuesReader rlReader = page.getRlEncoding().getValuesReader(descriptor, REPETITION_LEVEL);

sql/core/src/main/java/org/apache/spark/sql/execution/datasources/parquet/VectorizedDeltaBinaryPackedReader.java

@@ -0,0 +1,93 @@
+/*
+ * 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.spark.sql.execution.datasources.parquet;
+
+import org.apache.parquet.bytes.ByteBufferInputStream;
+import org.apache.parquet.column.values.ValuesReader;
+import org.apache.parquet.column.values.delta.DeltaBinaryPackingValuesReader;
+import org.apache.parquet.io.api.Binary;
+import org.apache.spark.sql.execution.vectorized.WritableColumnVector;
+
+import java.io.IOException;
+
+/**
+ * An implementation of the Parquet DELTA_BINARY_PACKED decoder
+ * that supports the vectorized interface.
+ */
+public class VectorizedDeltaBinaryPackedReader extends ValuesReader
+    implements VectorizedValuesReader {
+  private final DeltaBinaryPackingValuesReader valuesReader = new DeltaBinaryPackingValuesReader();
+
+  @Override
+  public void initFromPage(int valueCount, ByteBufferInputStream in) throws IOException {
+    valuesReader.initFromPage(valueCount, in);
+  }
+
+  @Override
+  public void skip() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public byte readByte() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public Binary readBinary(int len) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readBooleans(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readBytes(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readIntegers(int total, WritableColumnVector c, int rowId) {
+    for (int i = 0; i < total; i++) {
+      c.putInt(rowId + i, valuesReader.readInteger());
+    }
+  }
+
+  @Override
+  public void readLongs(int total, WritableColumnVector c, int rowId) {
+    for (int i = 0; i < total; i++) {
+      c.putLong(rowId + i, valuesReader.readLong());
+    }
+  }
+
+  @Override
+  public void readFloats(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readDoubles(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readBinary(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+}

sql/core/src/main/java/org/apache/spark/sql/execution/datasources/parquet/VectorizedDeltaByteArrayReader.java

@@ -0,0 +1,99 @@
+/*
+ * 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.spark.sql.execution.datasources.parquet;
+
+import org.apache.parquet.bytes.ByteBufferInputStream;
+import org.apache.parquet.column.values.ValuesReader;
+import org.apache.parquet.column.values.deltastrings.DeltaByteArrayReader;
+import org.apache.parquet.io.api.Binary;
+import org.apache.spark.sql.execution.vectorized.WritableColumnVector;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+/**
+ * An implementation of the Parquet DELTA_BYTE_ARRAY decoder that supports the vectorized interface.
+ */
+public class VectorizedDeltaByteArrayReader extends ValuesReader implements VectorizedValuesReader {
+  private final DeltaByteArrayReader deltaByteArrayReader = new DeltaByteArrayReader();
+
+  @Override
+  public void initFromPage(int valueCount, ByteBufferInputStream in) throws IOException {
+    deltaByteArrayReader.initFromPage(valueCount, in);
+  }
+
+  @Override
+  public void skip() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public byte readByte() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public Binary readBinary(int len) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readBooleans(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readBytes(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readIntegers(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readLongs(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readFloats(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readDoubles(int total, WritableColumnVector c, int rowId) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void readBinary(int total, WritableColumnVector c, int rowId) {
+    for (int i = 0; i < total; i++) {
+      Binary binary = deltaByteArrayReader.readBytes();
+      ByteBuffer buffer = binary.toByteBuffer();
+      if (buffer.hasArray()) {
+        c.putByteArray(rowId + i, buffer.array(), buffer.arrayOffset() + buffer.position(),
+          binary.length());
+      } else {
+        byte[] bytes = new byte[binary.length()];
+        buffer.get(bytes);
+        c.putByteArray(rowId + i, bytes);
+      }
+    }
+  }
+}

sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/parquet/ParquetEncodingSuite.scala

@@ -18,8 +18,12 @@ package org.apache.spark.sql.execution.datasources.parquet
 
 import scala.collection.JavaConverters._
 
+import org.apache.hadoop.fs.Path
+import org.apache.parquet.column.{Encoding, ParquetProperties}
 import org.apache.parquet.hadoop.ParquetOutputFormat
 
+import org.apache.spark.sql.Row
+import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.test.SharedSQLContext
 
 // TODO: this needs a lot more testing but it's currently not easy to test with the parquet
@@ -114,4 +118,36 @@ class ParquetEncodingSuite extends ParquetCompatibilityTest with SharedSQLContex
       }
     }
   }
+
+  test("parquet v2 pages - delta encoding") {
+    val extraOptions = Map[String, String](
+      ParquetOutputFormat.WRITER_VERSION -> ParquetProperties.WriterVersion.PARQUET_2_0.toString,
+      ParquetOutputFormat.ENABLE_DICTIONARY -> "false"
+    )
+
+    val hadoopConf = spark.sessionState.newHadoopConfWithOptions(extraOptions)
+    withSQLConf(SQLConf.PARQUET_VECTORIZED_READER_ENABLED.key -> "true",
+      ParquetOutputFormat.JOB_SUMMARY_LEVEL -> "ALL") {
+      withTempPath { dir =>
+        val path = s"${dir.getCanonicalPath}/test.parquet"
+        val data = (1 to 3).map { i =>
+          (i, i.toLong, s"test_${i}")
+        }
+
+        spark.createDataFrame(data).write.options(extraOptions).mode("overwrite").parquet(path)
+
+        val blockMetadata = readFooter(new Path(path), hadoopConf).getBlocks.asScala.head
+        val columnChunkMetadataList = blockMetadata.getColumns.asScala
+
+        // Verify that indeed delta encoding is used for each column
+        assert(columnChunkMetadataList.length === 3)
+        assert(columnChunkMetadataList(0).getEncodings.contains(Encoding.DELTA_BINARY_PACKED))
+        assert(columnChunkMetadataList(1).getEncodings.contains(Encoding.DELTA_BINARY_PACKED))
+        assert(columnChunkMetadataList(2).getEncodings.contains(Encoding.DELTA_BYTE_ARRAY))
+
+        val actual = spark.read.parquet(path).collect
+        assert(actual.sortBy(_.getInt(0)) === data.map(Row.fromTuple));
+      }
+    }
+  }
 }