下面是一个简单的程序：
将记录写入orc文件
然后尝试使用 predicate 下推读取文件( searchArgument )
问题：
这是在orc中使用 predicate 下推的正确方法吗？
这个 read(..) 方法似乎返回所有记录，完全忽略 searchArguments . 为什么？
笔记：
我还没有找到任何有用的单元测试来演示orc（github上的orc）中 predicate 下推的工作方式。我也找不到任何关于这个特性的清晰文档。我试着查看spark和presto代码，但没有找到任何有用的东西。
下面的代码是https://github.com/melanio/codecheese-blog-examples/tree/master/orc-examples/src/main/java/codecheese/blog/examples/orc

public class TestRoundTrip {
public static void main(String[] args) throws IOException {
    final String file = "tmp/test-round-trip.orc";
    new File(file).delete();
    final long highestX = 10000L;
    final Configuration conf = new Configuration();
    write(file, highestX, conf);
    read(file, highestX, conf);
}
private static void read(String file, long highestX, Configuration conf) throws IOException {
    Reader reader = OrcFile.createReader(
            new Path(file),
            OrcFile.readerOptions(conf)
    );
    //Retrieve x that is "highestX - 1000". So, only 1 value should've been retrieved.
    Options readerOptions = new Options(conf)
            .searchArgument(
                    SearchArgumentFactory
                            .newBuilder()
                            .equals("x", Type.LONG, highestX - 1000)
                            .build(),
                    new String[]{"x"}
            );
    RecordReader rows = reader.rows(readerOptions);
    VectorizedRowBatch batch = reader.getSchema().createRowBatch();
    while (rows.nextBatch(batch)) {
        LongColumnVector x = (LongColumnVector) batch.cols[0];
        LongColumnVector y = (LongColumnVector) batch.cols[1];
        for (int r = 0; r < batch.size; r++) {
            long xValue = x.vector[r];
            long yValue = y.vector[r];
            System.out.println(xValue + ", " + yValue);
        }
    }
    rows.close();
}
private static void write(String file, long highestX, Configuration conf) throws IOException {
    TypeDescription schema = TypeDescription.fromString("struct<x:int,y:int>");
    Writer writer = OrcFile.createWriter(
            new Path(file),
            OrcFile.writerOptions(conf).setSchema(schema)
    );
    VectorizedRowBatch batch = schema.createRowBatch();
    LongColumnVector x = (LongColumnVector) batch.cols[0];
    LongColumnVector y = (LongColumnVector) batch.cols[1];
    for (int r = 0; r < highestX; ++r) {
        int row = batch.size++;
        x.vector[row] = r;
        y.vector[row] = r * 3;
        // If the batch is full, write it out and start over.
        if (batch.size == batch.getMaxSize()) {
            writer.addRowBatch(batch);
            batch.reset();
        }
    }
    if (batch.size != 0) {
        writer.addRowBatch(batch);
        batch.reset();
    }
    writer.close();
}

}