Examples with ColumnDescriptor parquet.column.ColumnDescriptor used on opensource projects

Example 6 with ColumnDescriptor

use of parquet.column.ColumnDescriptor in project presto by prestodb.

the class ParquetPredicateUtils method getDictionariesByColumnOrdinal.

private static Map<Integer, ParquetDictionaryDescriptor> getDictionariesByColumnOrdinal(BlockMetaData blockMetadata, ParquetDataSource dataSource, MessageType requestedSchema, TupleDomain<HiveColumnHandle> effectivePredicate) {
    ImmutableMap.Builder<Integer, ParquetDictionaryDescriptor> dictionaries = ImmutableMap.builder();
    for (int ordinal = 0; ordinal < blockMetadata.getColumns().size(); ordinal++) {
        ColumnChunkMetaData columnChunkMetaData = blockMetadata.getColumns().get(ordinal);
        for (int i = 0; i < requestedSchema.getColumns().size(); i++) {
            ColumnDescriptor columnDescriptor = requestedSchema.getColumns().get(i);
            if (isColumnPredicate(columnDescriptor, effectivePredicate) && columnChunkMetaData.getPath().equals(ColumnPath.get(columnDescriptor.getPath())) && isOnlyDictionaryEncodingPages(columnChunkMetaData.getEncodings())) {
                try {
                    int totalSize = toIntExact(columnChunkMetaData.getTotalSize());
                    byte[] buffer = new byte[totalSize];
                    dataSource.readFully(columnChunkMetaData.getStartingPos(), buffer);
                    Optional<ParquetDictionaryPage> dictionaryPage = readDictionaryPage(buffer, columnChunkMetaData.getCodec());
                    dictionaries.put(ordinal, new ParquetDictionaryDescriptor(columnDescriptor, dictionaryPage));
                } catch (IOException ignored) {
                }
                break;
            }
        }
    }
    return dictionaries.build();
}