Spring Batch Job Restart: What should be the correct values for chunk and readerPageSize with respect to grid size.

[PSHREYASHOLLA]

This is posted here as I did not get a response on https://stackoverflow.com/questions/78199004/restarting-a-failed-job-is-not-processing-the-failed-chunk-data-again-continua

This is my step definition for spring batch partition approach,

@bean public Step step1() { return new StepBuilder("step1", jobRepository) .partitioner(slaveStep().getName(), partitioner()) .step(slaveStep()) .gridSize(febpEmployeeTaxCalculationBatchProperties.getTaxCalculationStep1PartitionGridSize()) .taskExecutor(actStmntTaskExecutor()) .build(); }

// slave step
@Bean
public Step slaveStep() 
{
    
    try {
        return new StepBuilder("slaveStep", jobRepository)
                .<EmployeeDetail, EmployeeTaxDetail>chunk(febpEmployeeTaxCalculationBatchProperties.getTaxCalculationStep1ReaderPageSize(),transactionManager)
                .reader(pagingItemReader(null,null))
                .processor(processor())
                .writer(customerItemWriter())
            .taskExecutor(actStmntTaskExecutor())
                .build();
    } catch (Exception ex) {
        throw new RuntimeException("Error creating slave step: " + ex.getMessage());
    }
}

/**

• Act stmnt task executor.
• @return the simple async task executor
  */
  public SimpleAsyncTaskExecutor actStmntTaskExecutor() {
  SimpleAsyncTaskExecutor acctStmtTaskExecuter = new SimpleAsyncTaskExecutor();
  acctStmtTaskExecuter.setConcurrencyLimit(febpEmployeeTaxCalculationBatchProperties.getTaxCalculationStep1TaskExecuterThreadConcurrencyLimit());
  acctStmtTaskExecuter.setThreadPriority(febpEmployeeTaxCalculationBatchProperties.getTaxCalculationStep1TaskExecuterThreadPriority());
  acctStmtTaskExecuter.setThreadNamePrefix("FEBP_TAX_CALCULATION_GEN");
  return acctStmtTaskExecuter;
  }

So here for restart to work,

1)Recommendation for restart is not using TaskExecuter. So should we not use TaskExecuter as mentioned above in step1() and slaveStep()? How to achieve concurrency ?

2. So only SimpleAsyncTaskExecutor needs to be used? If yes is it at step or slavestep?

3)How should the chunk size, gridSize and readers pagesize and fetchsiz be calculated? As I see if chunk size is set to low values, restart is not re-writting failed data.