public static Pair<ExternalScanOperatorDescriptor, AlgebricksPartitionConstraint> createExternalIndexingOp( JobSpecification spec, MetadataProvider metadataProvider, Dataset dataset, ARecordType itemType, RecordDescriptor indexerDesc, List<ExternalFile> files, SourceLocation sourceLoc) throws HyracksDataException, AlgebricksException { return getIndexingOperator(metadataProvider, spec, itemType, dataset, files == null ? MetadataManager.INSTANCE .getDatasetExternalFiles(metadataProvider.getMetadataTxnContext(), dataset) : files, indexerDesc, sourceLoc); }