How to persist a lot of entities (JPA)

Question

I need to process a CSV file and for each record (line) persist an entity. Right now, I do it this way:

while ((line = reader.readNext()) != null) {
    Enti         


        

Answer 1

To make it go faster, at least in Hibernate, you would do a flush() and a clear() after a certain number of inserts. I have done this approach for millions of records and it works. It's still slow, but it's much faster than not doing it. The basic structure is like this:

int i = 0;
for(MyThingy thingy : lotsOfThingies) {

    dao.save(thingy.toModel())

    if(++i % 20 == 0) {
        dao.flushAndClear();
    }

}