danielxjd commented on a change in pull request #12223:
URL: https://github.com/apache/beam/pull/12223#discussion_r481334035
##########
File path:
sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
##########
@@ -229,15 +279,259 @@ public void populateDisplayData(DisplayData.Builder
builder) {
public ReadFiles withAvroDataModel(GenericData model) {
return toBuilder().setAvroDataModel(model).build();
}
+ /** Enable the Splittable reading. */
+ public ReadFiles withSplit() {
+ return toBuilder().setSplittable(true).build();
+ }
@Override
public PCollection<GenericRecord> expand(PCollection<FileIO.ReadableFile>
input) {
checkNotNull(getSchema(), "Schema can not be null");
+ if (isSplittable()) {
+ return input
+ .apply(ParDo.of(new SplitReadFn(getAvroDataModel())))
+ .setCoder(AvroCoder.of(getSchema()));
+ }
return input
.apply(ParDo.of(new ReadFn(getAvroDataModel())))
.setCoder(AvroCoder.of(getSchema()));
}
+ @DoFn.BoundedPerElement
+ static class SplitReadFn extends DoFn<FileIO.ReadableFile, GenericRecord> {
+ private Class<? extends GenericData> modelClass;
+ private static final Logger LOG =
LoggerFactory.getLogger(SplitReadFn.class);
+ // Default initial splitting the file into blocks of 64MB. Unit of
SPLIT_LIMIT is byte.
+ private static final long SPLIT_LIMIT = 64000000;
+
+ SplitReadFn(GenericData model) {
+
+ this.modelClass = model != null ? model.getClass() : null;
+ }
+
+ ParquetFileReader getParquetFileReader(FileIO.ReadableFile file) throws
Exception {
+ ParquetReadOptions options =
HadoopReadOptions.builder(getConfWithModelClass()).build();
+ return ParquetFileReader.open(new
BeamParquetInputFile(file.openSeekable()), options);
+ }
+
+ @ProcessElement
+ public void processElement(
+ @Element FileIO.ReadableFile file,
+ RestrictionTracker<OffsetRange, Long> tracker,
+ OutputReceiver<GenericRecord> outputReceiver)
+ throws Exception {
+ LOG.debug(
+ "start "
+ + tracker.currentRestriction().getFrom()
+ + " to "
+ + tracker.currentRestriction().getTo());
+ ParquetReadOptions options =
HadoopReadOptions.builder(getConfWithModelClass()).build();
+ ParquetFileReader reader =
+ ParquetFileReader.open(new
BeamParquetInputFile(file.openSeekable()), options);
+ GenericData model = null;
+ if (modelClass != null) {
+ model = (GenericData) modelClass.getMethod("get").invoke(null);
+ }
+ ReadSupport<GenericRecord> readSupport = new
AvroReadSupport<GenericRecord>(model);
+
+ Filter filter = checkNotNull(options.getRecordFilter(), "filter");
+ Configuration hadoopConf = ((HadoopReadOptions) options).getConf();
+ FileMetaData parquetFileMetadata =
reader.getFooter().getFileMetaData();
+ MessageType fileSchema = parquetFileMetadata.getSchema();
+ Map<String, String> fileMetadata =
parquetFileMetadata.getKeyValueMetaData();
+
+ ReadSupport.ReadContext readContext =
+ readSupport.init(
+ new InitContext(
+ hadoopConf, Maps.transformValues(fileMetadata,
ImmutableSet::of), fileSchema));
+ ColumnIOFactory columnIOFactory = new
ColumnIOFactory(parquetFileMetadata.getCreatedBy());
+ MessageType requestedSchema = readContext.getRequestedSchema();
+ RecordMaterializer<GenericRecord> recordConverter =
+ readSupport.prepareForRead(hadoopConf, fileMetadata, fileSchema,
readContext);
+ reader.setRequestedSchema(requestedSchema);
+ MessageColumnIO columnIO =
columnIOFactory.getColumnIO(requestedSchema, fileSchema, true);
+ long currentBlock = tracker.currentRestriction().getFrom();
+ for (int i = 0; i < currentBlock; i++) {
+ reader.skipNextRowGroup();
+ }
+
+ while ((tracker).tryClaim(currentBlock)) {
+ PageReadStore pages = reader.readNextRowGroup();
+ LOG.debug("block {} read in memory. row count = {}", currentBlock,
pages.getRowCount());
+ currentBlock += 1;
+ RecordReader<GenericRecord> recordReader =
+ columnIO.getRecordReader(
+ pages, recordConverter, options.useRecordFilter() ? filter :
FilterCompat.NOOP);
+ long currentRow = 0;
+ long totalRows = pages.getRowCount();
+ while (currentRow < totalRows) {
Review comment:
I have tried that once and it might have some issue when reading out of
the range, the original ParquetReader also tracked the row number when reading.
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