Optimizing Hibernate session.createQuery().list();

Question

We have a Users table (MySQL) with 120,000 rows

List<User> users = session.createQuery("from User").list();

This hibernate query takes about 6 to 9 seconds to execute. How can we optimize this? Is MySQL the bottleneck? Or is .list() usually this slow?

Answer 1

Ofcourse it's slow because the query perform the full table scan. You should join other objects associated with it, including where clause of the query, the query could be changed to return the limited number of records or use criteria API and projection.

Answer 2

Use pagination on your query. You should not call all rows at a time. You can set first position of result and maximum result. For example, if you want to read first 100 result than change your query like:

Query q=session.createQuery("from User");
q.setFirstResult(fistRes);// this will variable
q.setMaxResults(maxRes);// this will also be variable as parameter.