Difference between fetch_size and page_size in JDBC input

Question

I'm using Logstash to import a lot of data from a MySQL database. I'm facing a java.lang.OutOfMemoryError: Java heap space error. After a few searches I found out a good solution is to enable paging (here) and set jdbc_page_size.

In the current conf I use, the jdbc_fetch_size is already set.

Now, my questions are:

• What are the differences between those two parameters?
• Do they interact? In a opposite or similar way?

The info I gathered so far are:

• this topic asking if :

jdbc_page_size determines the number of rows that are fetched from database per trip

• And this one, about hibernate, stating that:

hibernate.jdbc.fetch_size determines the number of rows fetched when there is more than a one row result on select statements

And of course logstash doc

Can anyone clarify it?