Examples with ColumnMetaData parquet.format.ColumnMetaData used on opensource projects

Example 1 with ColumnMetaData

use of parquet.format.ColumnMetaData in project presto by prestodb.

the class ParquetMetadataReader method readFooter.

public static ParquetMetadata readFooter(FileSystem fileSystem, Path file) throws IOException {
    FileStatus fileStatus = fileSystem.getFileStatus(file);
    try (FSDataInputStream inputStream = fileSystem.open(file)) {
        // Parquet File Layout:
        //
        // MAGIC
        // variable: Data
        // variable: Metadata
        // 4 bytes: MetadataLength
        // MAGIC
        long length = fileStatus.getLen();
        validateParquet(length >= MAGIC.length + PARQUET_METADATA_LENGTH + MAGIC.length, "%s is not a valid Parquet File", file);
        long metadataLengthIndex = length - PARQUET_METADATA_LENGTH - MAGIC.length;
        inputStream.seek(metadataLengthIndex);
        int metadataLength = readIntLittleEndian(inputStream);
        byte[] magic = new byte[MAGIC.length];
        inputStream.readFully(magic);
        validateParquet(Arrays.equals(MAGIC, magic), "Not valid Parquet file: %s expected magic number: %s got: %s", file, Arrays.toString(MAGIC), Arrays.toString(magic));
        long metadataIndex = metadataLengthIndex - metadataLength;
        validateParquet(metadataIndex >= MAGIC.length && metadataIndex < metadataLengthIndex, "Corrupted Parquet file: %s metadata index: %s out of range", file, metadataIndex);
        inputStream.seek(metadataIndex);
        FileMetaData fileMetaData = readFileMetaData(inputStream);
        List<SchemaElement> schema = fileMetaData.getSchema();
        validateParquet(!schema.isEmpty(), "Empty Parquet schema in file: %s", file);
        MessageType messageType = readParquetSchema(schema);
        List<BlockMetaData> blocks = new ArrayList<>();
        List<RowGroup> rowGroups = fileMetaData.getRow_groups();
        if (rowGroups != null) {
            for (RowGroup rowGroup : rowGroups) {
                BlockMetaData blockMetaData = new BlockMetaData();
                blockMetaData.setRowCount(rowGroup.getNum_rows());
                blockMetaData.setTotalByteSize(rowGroup.getTotal_byte_size());
                List<ColumnChunk> columns = rowGroup.getColumns();
                validateParquet(!columns.isEmpty(), "No columns in row group: %s", rowGroup);
                String filePath = columns.get(0).getFile_path();
                for (ColumnChunk columnChunk : columns) {
                    validateParquet((filePath == null && columnChunk.getFile_path() == null) || (filePath != null && filePath.equals(columnChunk.getFile_path())), "all column chunks of the same row group must be in the same file");
                    ColumnMetaData metaData = columnChunk.meta_data;
                    String[] path = metaData.path_in_schema.toArray(new String[metaData.path_in_schema.size()]);
                    ColumnPath columnPath = ColumnPath.get(path);
                    ColumnChunkMetaData column = ColumnChunkMetaData.get(columnPath, messageType.getType(columnPath.toArray()).asPrimitiveType().getPrimitiveTypeName(), CompressionCodecName.fromParquet(metaData.codec), readEncodings(metaData.encodings), readStats(metaData.statistics, messageType.getType(columnPath.toArray()).asPrimitiveType().getPrimitiveTypeName()), metaData.data_page_offset, metaData.dictionary_page_offset, metaData.num_values, metaData.total_compressed_size, metaData.total_uncompressed_size);
                    blockMetaData.addColumn(column);
                }
                blockMetaData.setPath(filePath);
                blocks.add(blockMetaData);
            }
        }
        Map<String, String> keyValueMetaData = new HashMap<>();
        List<KeyValue> keyValueList = fileMetaData.getKey_value_metadata();
        if (keyValueList != null) {
            for (KeyValue keyValue : keyValueList) {
                keyValueMetaData.put(keyValue.key, keyValue.value);
            }
        }
        return new ParquetMetadata(new parquet.hadoop.metadata.FileMetaData(messageType, keyValueMetaData, fileMetaData.getCreated_by()), blocks);
    }
}