[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-1718) Have multiple bag fetches revert to subselect fetching for all but one of the bags

[Geoffrey De Smet (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-1718?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_28449 ] 

Geoffrey De Smet commented on HHH-1718:
---------------------------------------

Using sets instead of bags leads to cartesian products being fetched.

I've just tried switching to sets instead of bags, and although the query now executes, it's terrible on a medium to large dataset as it creates a cartesian product. Reverting to subselect for parallel collections would indeed fix that too and could actually be a lot better for multiple sets too.

> Have multiple bag fetches revert to subselect fetching for all but one of the bags
> ----------------------------------------------------------------------------------
>
>                 Key: HHH-1718
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1718
>             Project: Hibernate3
>          Issue Type: Improvement
>          Components: core, query-criteria, query-hql
>            Reporter: Steve Ebersole
>            Assignee: Steve Ebersole
>             Fix For: hql+collection
>
>         Attachments: hibernate_eksempel.zip
>
>
> Follow on to HHH-1413.  Multiple bag fetches were simply disallowed as the resolution to that particular case in the interest of working around that issue.
> The correct longer term solution is to not fetch all the bags at once, ideally reverting to subselect fetching for all but one of the bags.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira