Example of parquet vectorized reading

Main.java

// http://www.jofre.de/?p=1459
package de.jofre.test;
import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.parquet.column.page.PageReadStore;
import org.apache.parquet.example.data.Group;
import org.apache.parquet.example.data.simple.convert.GroupRecordConverter;
import org.apache.parquet.format.converter.ParquetMetadataConverter;
import org.apache.parquet.hadoop.ParquetFileReader;
import org.apache.parquet.hadoop.metadata.ParquetMetadata;
import org.apache.parquet.io.ColumnIOFactory;
import org.apache.parquet.io.MessageColumnIO;
import org.apache.parquet.io.RecordReader;
import org.apache.parquet.schema.MessageType;
import org.apache.parquet.schema.Type;

public class Main {

  private static Path path = new Path("file:\\C:\\myfile.snappy.parquet");

  private static void printGroup(Group g) {
    int fieldCount = g.getType().getFieldCount();
    for (int field = 0; field < fieldCount; field++) {
      int valueCount = g.getFieldRepetitionCount(field);

      Type fieldType = g.getType().getType(field);
      String fieldName = fieldType.getName();

      for (int index = 0; index < valueCount; index++) {
        if (fieldType.isPrimitive()) {
          System.out.println(fieldName + " " + g.getValueToString(field, index));
        }
      }
    }
    System.out.println("");
  }

  public static void main(String[] args) throws IllegalArgumentException {

    Configuration conf = new Configuration();

    try {
      ParquetMetadata readFooter = ParquetFileReader.readFooter(conf, path, ParquetMetadataConverter.NO_FILTER);
      MessageType schema = readFooter.getFileMetaData().getSchema();
      ParquetFileReader r = new ParquetFileReader(conf, path, readFooter);

      PageReadStore pages = null;
      try {
        while (null != (pages = r.readNextRowGroup())) {
          final long rows = pages.getRowCount();
          System.out.println("Number of rows: " + rows);

          final MessageColumnIO columnIO = new ColumnIOFactory().getColumnIO(schema);
          final RecordReader recordReader = columnIO.getRecordReader(pages, new GroupRecordConverter(schema));
          for (int i = 0; i < rows; i++) {
            final Group g = recordReader.read();
            printGroup(g);

            // TODO Compare to System.out.println(g);
          }
        }
      } finally {
        r.close();
      }
    } catch (IOException e) {
      System.out.println("Error reading parquet file.");
      e.printStackTrace();
    }
  }
}