FileSystem fs = new CachedSingleFileSystem(fileName);
BufferAllocator allocator = new TopLevelAllocator();
for(int i = 0; i < 25; i++) {
ParquetRecordReader rr = new ParquetRecordReader(context, 256000, fileName, 0, fs,
new CodecFactoryExposer(dfsConfig), f.getParquetMetadata(), columns);
TestOutputMutator mutator = new TestOutputMutator(allocator);
rr.setup(mutator);
Stopwatch watch = new Stopwatch();
watch.start();
int rowCount = 0;