scrollableresults

I was reading a blog regarding bulk fetching with hibernate http://java.dzone.com/articles/bulk-fetching-hibernate . In this, ScrollableResults is used as a solution. Here still we need to evict objects from session. I don't understand how using ScrollableResults (or scroll() ) is different from using list() . In other words, how the below statements differ in terms of performance List<Employee> empList = session.createCriteria(Employee.class).list(); ScrollableResults sc = session.createCriteria(Employee.class).scroll(); Please let me know. I referred Hibernate API documentation to understand

For instance, I have a table with two fields: id, value. I've inserted almost 100k rows in this table. I want to use scrollable cursor. I wrote the following code: <?php ... $sql = 'SELECT id FROM cursor_test;'; $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL)); $stmt->execute(); $row = $stmt->fetch(PDO::FETCH_ASSOC, PDO::FETCH_ORI_ABS, 3); var_dump($row['id']); // 1, expected value is 3 What am I doing wrong? egemadra Seems that mysql does not support scrollable cursors. https://bugs.php.net/bug.php?id=34625 http://www.php.net/manual/en/pdostatement.fetch.php#105277

I simply need to read each row in a table in my MySQL database using Hibernate and write a file based on it. But there are 90 million rows and they are pretty big. So it seemed like the following would be appropriate: ScrollableResults results = session.createQuery("SELECT person FROM Person person") .setReadOnly(true).setCacheable(false).scroll(ScrollMode.FORWARD_ONLY); while (results.next()) storeInFile(results.get()[0]); The problem is the above will try and load all 90 million rows into RAM before moving on to the while loop... and that will kill my memory with OutOfMemoryError: Java heap