[CAY-2349] Cayenne cache issue: 'SelectQuery' with prefetches loses relationships (null)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.B1
• Fix Version/s: 4.0.B2, 4.1.M1
• Component/s: Core Library
• Environment: JCacheModule, ehcache.
• Assignee: Nikita Timofeev
• Reporter: Artyom Kravchenko
• Created: 16/Aug/17 06:52
• Updated: 10/Sep/17 11:43
• Resolved: 16/Aug/17 11:01

Description

I have faced with the problem when SelectQuery returns wrong query result: returned object lost some of the relationships - they are null.

I have used prefetches (to load several number of objects in one go) and shared cache (to put query result to cache). I have found an use case where it always reproduces, see my test:

class CayenneJCacheTest {

    def cayenneRuntime

    @Test
    void test() {
        cayenneRuntime = new ServerRuntime("cayenne-project.xml", new JCacheModule())
       //select single artist with limited prefetch graph
        selectFew()
       //do the same query but with additional prefetches
        List<Artist> artists =  selectMore()
       // all actor's paintings has a gallery but it is lost from query result - test failed
        assertNotNull(artists[0].paintings[0].gallery)
    }


    List<Artist> selectFew() {
        //prefetch artist.paintings only, do not prefetch   artist.paintings.gallery
        ObjectSelect.query(CourseClass)
                .where(Artist.ID.eq('1001'))
                .prefetch(Artist.PAINTINGS.joint())
                .cacheStrategy(QueryCacheStrategy.SHARED_CACHE)
                .cacheGroup(Artist.class.simpleName)
                .select(cayenneRuntime.newContext())
    }
    
     List<Artist> selectFew() {
        //prefetch all related objects
        ObjectSelect.query(CourseClass)
                .where(Artist.ID.eq('1001'))
                .prefetch(Artist.PAINTINGS.joint())
                .prefetch(Artist.PAINTINGS.dot(Painting.GALLERY).joint())
                .cacheStrategy(QueryCacheStrategy.SHARED_CACHE)
                .cacheGroup(Artist.class.simpleName)
                .select(cayenneRuntime.newContext())
    }
    
}