In hibernate we will get data in different ways like:
.get().load()- HQL
- NativeSQL
- etc.
But which one is best in terms of performance?
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1Welcome to Stack Overflow. I'm afraid we will not be able to help you since your question lacks detail. Please read stackoverflow.com/questions/how-to-askuser647772– user6477722012-02-03 11:17:01 +00:00Commented Feb 3, 2012 at 11:17
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1 Answer
Basic rules for fetching data in Hibernate with respect to performance are:
- Don't fetch more data than you need
- Fetch data that you need with minimal number of queries
- Make sure that DBMS generates optimal query plans for your queries
Following these rules requires different approaches in different situations. For example:
Use
get()to fetch a single object by its id. Configure fetch types of its relationships (lazy/eager) to achieve optimal balance between rules 1 and 2.Sometimes you need to obtain a reference to the object, but don't need to fetch it. Use
load()in this case to avoid fetching unnecessary data.Use HQL queries to fetch multiple objects. Tune fetch strategy with
join fetchfor optimal balance between rules 1 and 2.Sometimes you need to use different fetch strategies in different scenarios in order to achieve balance between rules 1 and 2, so that static fetch type settings are not enough. In this case use HQL queries tuned for particular scenarios, even when fetching single objects.
Fetch profiles introduced in Hibernate 3.5 may help as well.
Sometimes your DBMS cannot build optimal query plans for queries generated by Hibernate. Use native SQL in this case.
