[Hibernate-issues] [Hibernate-JIRA] Closed: (HHH-1776) Extra Lazy collection, wrong size

[Steve E. (JIRA) <no...@at...>]

     [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-1776?page=all ]
     
Steve Ebersole closed HHH-1776:
-------------------------------

    Resolution: Rejected
     Assign To: Steve Ebersole

You actually have the collection mapped incorrectly.  You attempt to use the primary key of the collection elements as the list index.  list-index refers to the index or position of the elements within the list, which in fact must be sequential.

lazy=extra is intended for *huge* collections.  Across such data sets, a "select max(...)" query will be much faster that a "select count(...)" query.  That, coupled with the fact mentioned above, is why the max() query is used instead of the count() query

> Extra Lazy collection, wrong size
> ---------------------------------
>
>          Key: HHH-1776
>          URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1776
>      Project: Hibernate3
>         Type: Bug

>     Versions: 3.2.0.cr2
>  Environment: HSQLDB 1.8.0.4
>     Reporter: Ecmel Ercan
>     Assignee: Steve Ebersole

>
>
> I have the following mappings: 
> <hibernate-mapping> 
>     <class name="TestParent" table="TESTPARENT"> 
>         <id name="id" column="ID"> 
>             <generator class="native"/> 
>         </id> 
>         <list name="children" lazy="extra"> 
>             <key column="PARENT_ID" /> 
>             <list-index column="id"/> 
>             <one-to-many class="TestChild" /> 
>         </list> 
>                 
>     </class> 
>     
> </hibernate-mapping> 
> <hibernate-mapping> 
>     <class name="TestChild" table="TESTCHILD"> 
>         <id name="id" column="ID"> 
>             <generator class="native"/> 
>         </id> 
>                 
>         <many-to-one name="parent" column="id" class="TestParent" />        
>     
>     </class> 
>   
> </hibernate-mapping> 
> When I get the size of the children by: 
> System.out.println(parent.getChildren().size()); 
> the following query is issued: 
> select max(id) + 1 from TESTCHILD where PARENT_ID =? 
> This assumes a sequential id column with no deleted rows. I expect a count(id) query. 
> Strangely, if I map the same class with annotations, a count(id) query is issued, but the collection will not be extra lazy as I mentioned in the annotations forum: http://forum.hibernate.org/viewtopic.php?t=959249

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