[Hibernate-issues] [Hibernate-JIRA] Updated: (HB-12) low performance loading with optional 1-1 association

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The following issue has been updated:

    Updater: Gavin King (mailto:ga...@hi...)
       Date: Sun, 9 Nov 2003 9:43 AM
    Comment:
Now also implemented for HQL FETCH clause. Other cases much less important.
    Changes:
             priority changed from Major
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  http://opensource.atlassian.com/projects/hibernate/secure/ViewIssue.jspa?key=HB-12&page=history

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View the issue:

  http://opensource.atlassian.com/projects/hibernate/secure/ViewIssue.jspa?key=HB-12


Here is an overview of the issue:
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        Key: HB-12
    Summary:  low performance loading with optional 1-1 association
       Type: Bug

     Status: In Progress
   Priority: Minor

    Project: Hibernate2

   Assignee: Gavin King
   Reporter: Max Rydahl Andersen

    Created: Sat, 3 May 2003 10:02 AM
    Updated: Sun, 9 Nov 2003 9:43 AM

Description:
low performance loading with optional 1-1 association
I use Hibernate 1.2.3. 

There is a problem, which causes a severe performance loss: 

If you have 2 entites (A and B) with a 1-1 association, 
Hibernate uses an SQL query with a join (if enabled) to 
load both entites with 1 statement. Wonderful! If there 
is a B for an A, everything is okay. 

If there is no B for a certain A, Hibernate tries 
(although the 1st statment returned no instance for B) 
to load B, when you invoke the corresponding getter, 
which results in an unnecessary SQL query! 

If there are many entities associated, there are many 
unnecessesary SQL queries and the performance suffers. 

Thanks 
Markus 

(Original: http://sourceforge.net/tracker/index.php?func=detail&aid=686577&group_id=40712&atid=428708)


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