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Bug 324459

Summary:

Potential deadlock when using fetch joins

Product:

z_Archived

Reporter:

Tom Ware <tom.ware>

Component:

Eclipselink

Assignee:

Nobody - feel free to take it <nobody>

Status:

CLOSED FIXED

QA Contact:

Severity:

normal

Priority:

CC:

christopher.delahunt, michael.f.obrien

Version:

unspecified

Target Milestone:

---

Hardware:

OS:

Windows XP

Whiteboard:

Attachments:

Description	Flags
Potential fix	none
Suggested fix with test case	none
Updated patch	none
Updated patch	none
Updated patch on 2.1.2 stream	none

Description Tom Ware

2010-09-03 13:38:55 EDT

Deferred locking settings are not maintained when using fetch joins.

This bug should be reproducable in a way very similar to Bug 262157, except with a Fetch join in the place where Inheritance was causing the issue.

Attaching a potential patch.  A test case will follow

Comment 1 Tom Ware

2010-09-03 13:41:00 EDT

Created attachment 178181 [details]
Potential fix

Comment 2 Tom Ware

2010-09-03 13:41:35 EDT

Attached a potential fix which cascades the deferred locking settings to object builds for fetch joins.

Comment 3 Tom Ware

2010-09-17 15:58:40 EDT

The deadlock occurs in the following situation

- Bidirectional relationship between A and B
- B has no EAGER ForeignReferenceMappings and, hence, will use Active Locking by default
- A->B is EAGER
- B->A is LAZY
- Query1 is ReadObjectQuery for A
- Query 2 is ReadObjectQuery for B with a fetch join to A
- Run Query 1 and stop it after it gets the lock for A, but before it gets the lock for B
- Run Query 2
- Allow Query 1 to continue

Query 1 will deadlock when it tries to get an active lock for A.

Comment 4 Tom Ware

2010-09-17 16:00:19 EDT

Created attachment 179147 [details]
Suggested fix with test case

Comment 5 Tom Ware

2010-09-17 16:01:15 EDT

The attached fix cascades deferred locking settings for any object that uses deferred locking to any additional EAGER or Joined attributes retrieved by the same query.

Comment 6 Tom Ware

2010-09-22 10:21:07 EDT

Created attachment 179381 [details]
Updated patch

Comment 7 Tom Ware

2010-09-22 15:01:49 EDT

Created attachment 179400 [details]
Updated patch

Comment 8 Tom Ware

2010-09-23 13:55:26 EDT

Fixed in trunk.

Reviewed by James Sutherland and Gordon Yorke

Added test to simultaneous test model

Comment 9 Chris Delahunt

2010-10-28 14:59:31 EDT

Fix also checked into 2.1.2
Completed: At revision: 8437

Comment 10 Peter Krogh

2010-10-29 10:15:32 EDT

Created attachment 182037 [details]
Updated patch on 2.1.2 stream

Comment 11 Eclipse Webmaster

2022-06-09 10:31:07 EDT

The Eclipselink project has moved to Github: https://github.com/eclipse-ee4j/eclipselink