Hi, I'm rather new to hibernate (i know how to use it, but no deeper understandings of the mechanics) and have run into a problem.

I have the problem that I'm not sure what gives the best performance of either retrieving whole objects/tables from the database or only retrieving the specific columns that are required for a specific piece of functionality.

I keep telling myself that if the columns in a table are used in different functionalities, then it might be better performance-wise to retrieve whole objects/tables, since it will only be retrieved once from the database and following queries will be fetched from the cache. Whereas seperate queries will be executed if I retrieve different columns from the same table.

So, are there any guidelines as to what is best practice when querying for data?

Doesn't it depend on your application?

Say you have two related objects A and B. If when A is retrieved and used, B is almost always used with it, then it makes sense to retrieve both in one shot, but if B is not used so often, then it makes sense to lazy-load it.

Don't worry so much about performance optimization until you have to. It's a waste of your time and the bottleneck usually isn't where you think it is. :)

Hi,

Can you give more specific details than giving us generic details.

It would helps us to help you out whether optimization is required or not.

I would like to differ with the other poster
Beauty of a programmer is when you write a clean and performance oriented code which keeps you application faster and easy to maintain.

Hi again, I'll try to be a bit more specific then ;-)

Here's a snapshot of a table in the database(mysql), which is used on a website:



Where text columns can be up to 65656 chars and "owner" is a FK

These are some of the scenarios where data needs to be retrieved:

1. all columns

2. teamid, teamname, division

3. bio

4. logo

5. teamname, logo, rating, division

6. teamname, rating

7. teamid, teamname, logo, divison, owner

8. teamid, reroll, ff, asscoach, cheer, apo, wizard

9. teamid, teamname, race, rating, treasury, owner

10. teamname

As to the frequency of them i cannot say since I don't have any statistics at hand.
I hope it can help clear up some confusion =)

Hi,

After looking through the table. I can figure out that you do quite lot of operations based on a single table.

To Optimize:
1) Lazy Load the Associations.
2) If your table value will not be modified frequently then you load the full object/table and then can get the values from the cache.
3) If your table is updated so often, then you can get values of specific column, It increases your performance.