[OPENJPA-2179] 'distinct' and 'join' combinations lead lots of unneccessary sub-queries for @Embedded and @Lob fields

• Type: Bug
• Status: In Progress
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.2.0
• Component/s: kernel
• Assignee: Mark Struberg
• Reporter: Mark Struberg
• Created: 26/Apr/12 17:00
• Updated: 05/Apr/15 16:16

Description

I have an Entity (Course) with a simple @Embedded field and a @Lob. I do not use any LAZY attribution on them!

If I do a normal em.find, the entity will be loaded as a whole (all the fields, including the embedded and the lob will be fetched immediately).
Sidenote: the Lecturer referred in the select is defined as
@OneToMany(mappedBy = "course",
cascade =

{CascadeType.PERSIST, CascadeType.REMOVE, CascadeType.MERGE}

,
orphanRemoval = true, fetch = FetchType.EAGER)
@OrderColumn(name = "POSITION")
private List<Lecturer> lecturers;

The following selects DO work

• "select c from Course c join c.lecturers l "
• "select distinct c from Course c"

The following selects create tons of subqueries! 1 separate sub-query for each @Embedded field, and also for each @Lob

• "select distinct c from Course c join c.lecturers l "
• "select distinct c from Lecturer l join l.course c"
• "select c from Lecturer l join l.course c"

This happens ONLY if I run this stuff against Oracle. In MySQL it seems to work properly.

I'll try to create a unit test for it.