Records omitted from query using JPAPagingitemReader

Question

In our project, we are dumping all the data which is required for batch processing in a temperory table in the first step. In the second step, we are reading data from the temperory table, processing it(processor) and deleting it from the same temp table(in JPAWriter). We are using JPAPagingItemReader and we face the same issue as many rows are getting skipped. The solution given in the link (i,e using JDBCPagingItemReader) is worked for me

Spring batch jpaPagingItemReader why some rows are not read?

I have few questions here,

1. Is it a right way to use JDBCPagingItemReader along with JPAPagingWriter??
2. Since a step will be executing in a transaction, Will it be problem if there a failure during processing/writing like rollback?
3. Any issue with respect to performance as we need to process 1 million records?
4. Any other approaches other than using JDBCPagingItemReader, please provide

Thanks

Answer 1

1. I can't think of a reason why it would be bad OOTB, but it will depend on your use case.
2. Spring Batch is designed to handle the transactionality of your steps. If there is a failure, it's Spring Batch's job to help out. I'd need to know more about the specific errors you're concerned with to be able to suggest exact solutions.
3. I'm not a fan of the JPA related stuff for performance related work. That being said, again, it depends on things like the complexity of your queries, how much data is being loaded, how long your window is to process 1 million records, etc to be able to say if it will be performant enough.
4. I recommend using the JdbcPagingItemReader. It's threadsafe so if you need to speed things along, there are things you can do to help.