Spring Batch Best Architecture to Read XML - spring

Question

What is the Best performance architecture to read XML in Spring Batch? Each XML is approximately 300 KB size and we are processing 1 Million.
Our Current Approach
30 partitions and 30 Grids and Each slave gets 166 XMLS
Commit Chunk 100
Application Start Memory is 8 GB
Using JAXB in Reader Default Bean Scope
#StepScope
#Qualifier("xmlItemReader")
public IteratorItemReader<BaseDTO> xmlItemReader(
#Value("#{stepExecutionContext['fileName']}") List<String> fileNameList) throws Exception {
String readingFile = "File Not Found";
logger.info("----StaxEventItemReader----fileName--->" + fileNameList.toString());
List<BaseDTO> fileList = new ArrayList<BaseDTO>();
for (String filePath : fileNameList) {
try {
readingFile = filePath.trim();
Invoice bill = (Invoice) getUnMarshaller().unmarshal(new File(filePath));
UnifiedInvoiceDTO unifiedDTO = new UnifiedInvoiceDTO(bill, environment);
unifiedDTO.setFileName(filePath);
BaseDTO baseDTO = new BaseDTO();
baseDTO.setUnifiedDTO(unifiedDTO);
fileList.add(baseDTO);
} catch (Exception e) {
UnifiedInvoiceDTO unifiedDTO = new UnifiedInvoiceDTO();
unifiedDTO.setFileName(readingFile);
unifiedDTO.setErrorMessage(e);
BaseDTO baseDTO = new BaseDTO();
baseDTO.setUnifiedDTO(unifiedDTO);
fileList.add(baseDTO);
}
}
return new IteratorItemReader<>(fileList);
}
Our questions:
Is this Archirecture correct
Is any performance or architecture advantage of using StaxEventItemReader and XStreamMarshaller over JAXB.
How to handle memory properly to avoid slow down

Answer 1

I would create a job per xml file by using the file name as a job parameter. This approach has many benefits:
Restartability: If a job fails, you only restart the failed file (from where it left off)
Scalability: This approach allows you to run multiple jobs in parallel. If a single machine is not enough, you can distribute the load on multiple machines
Logging: Logs are separate by design, you don't need to use an MDC or any other technique to separate logs
We are receiving XML filepath in a *.txt file
You can a create a script that iterates over these lines and launch a job per line (aka per file). Gnu Parallel (or a similar tool) is a good option to launch jobs in parallel.