JPQL构造函数执行需要很长时间

Question

I am using JPQL constructor in my code. It involves large results, 5024 data retrieved and objects created when executing this query. It is taking around 2 minutes to complete its execution. There are multiple tables involved to execute this query. I could not go for cache since the DB data will update daily. Is there any way to optimize the execution speed?

My SQL query formation is like this,

String sql = "SELECT DISTINCT "
                  + "new com.abc.dc.entity.market.LaptopData(vd.segment.id, vd.segment.segmentGroup, "
                  + "vd.segment.segmentName, vd.segment.category, "
                  + "vd.product.make, vd.product.model, vd.product.modelYear) "
                  + "FROM LaptopData vd, Profile p "
                  + "WHERE vd.profile.profileCode = :profileCode "
                  + "AND vd.pk.profileId = p.id "
                  + "Order By vd.segment.segmentGroup, vd.segment.segmentName, vd.product.make, vd.product.model,"
                  + " vd.product.modelYear asc";
Query query = em.createQuery(sql);
query.setParameter("profileCode", profileCode);

@SuppressWarnings("unchecked")
List<LaptopData> results = query.getResultList();

em.clear();
return results;

Answer 1

Well, one option for you is to create separate table which would contain result of this query for all entities and update it daily (every night) and then run your query on this new table, like this:

"SELECT DISTINCT"
              + "new com.abc.dc.entity.market.LaptopData(m.id, m.segmentGroup, "
              + "m.segmentName, m.category, "
              + "m.make, m.model, m.modelYear) "
              + "FROM someNewTable m"
              + "WHERE m.profileCode = :profileCode ";

This way you don't have to do join and ordering every time you execute your query, but only once a day when you generate new table. Ofcourse with this approach to see data updates you'll have to wait until new table is recreated.

Also, you can create indexes on fields you are using in where clause.