[Hibernate-JIRA] Created: (HHH-2575) Query results are mapped to object array incorrectly when there is column ambiguity and aliases are not used
by Mike Hoeffner (JIRA)
Query results are mapped to object array incorrectly when there is column ambiguity and aliases are not used
------------------------------------------------------------------------------------------------------------
Key: HHH-2575
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2575
Project: Hibernate3
Issue Type: Bug
Components: query-sql
Affects Versions: 3.2.2
Environment: Hibernate 3.2.2 + MySQL 5.0.22 + MySQL Connector/J 5.0.5. Reproduced with HSQLDB 1.8.0.7.
Reporter: Mike Hoeffner
Priority: Minor
Attachments: ResultsNotEffectedByAliasesTest.java
I had a SQL (not HQL) query that basically looked like this:
select a.name, a.seq, b.name, b.seq from foo a, foo b;
and I noticed that the results obtained through list() -> (Object[]) get(i) -> row[0], row[1], row[2], row[3]
did not correspond to what I saw when manually running the query without Hibernate involved. row[2] always had the same values as row[0] and row[3] always had the same values as row[1].
When I tried adding aliases so that it became:
select a.name as a_name, a.seq as a_seq, b.name as b_name, b.seq as b_seq from foo a, foo b;
then the results matched what I expected. So having aliases in the SQL modified the results that were returned even though I was looking up the value from each column by its index / position instead of by its name / alias.
Attached is a test case that will reproduce this.
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15 years
[Hibernate-JIRA] Created: (HHH-2661) Second-level cache is used after Session.setCacheMode(CacheMode.IGNORE)
by Anders Wallgren (JIRA)
Second-level cache is used after Session.setCacheMode(CacheMode.IGNORE)
-----------------------------------------------------------------------
Key: HHH-2661
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2661
Project: Hibernate3
Issue Type: Bug
Components: caching (L2)
Affects Versions: 3.2.4.sp1
Environment: Windows Vista
MySQL 5.0
Reporter: Anders Wallgren
I'm doing some bulk importing and want to disable the L2 cache, so I call Session.setCacheMode(CacheMode.IGNORE) before doing any work.
However, the entities I'm creating still end up in the cache. It seems that org.hibernate.action.CollectionAction isn't doing the correct check to determine when to cache -- it only check for the existence of a configured cache, but doesn't check whether caching is enabled in the session.
For example, from CollectionAction.beforeExecutions:
public final void beforeExecutions() throws CacheException {
// we need to obtain the lock before any actions are
// executed, since this may be an inverse="true"
// bidirectional association and it is one of the
// earlier entity actions which actually updates
// the database (this action is resposible for
// second-level cache invalidation only)
if ( persister.hasCache() ) {
final CacheKey ck = new CacheKey(
key,
persister.getKeyType(),
persister.getRole(),
session.getEntityMode(),
session.getFactory()
);
lock = persister.getCache().lock(ck, null);
}
}
Shouldn't "if ( persister.hasCache() )" be persistence.hasCache && getSession.getCacheMode.isPutEnabled(), or something along those lines?
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15 years
[Hibernate-JIRA] Created: (HHH-2668) Caching Fails with Composite-Ids Containing Nested, Complex Entities
by Juan Osuna (JIRA)
Caching Fails with Composite-Ids Containing Nested, Complex Entities
--------------------------------------------------------------------
Key: HHH-2668
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2668
Project: Hibernate3
Issue Type: Bug
Components: caching (L2)
Affects Versions: 3.2.4.sp1
Environment: Problem is independent of environment or platform and most likely exists in prior versions.
Reporter: Juan Osuna
Attachments: hibernate-caching-fix.zip
Description of Failing Test Case Scenario
Preconditions: An entity class is mapped that uses a composite-id that contains a nested entity class. Only the composite-id class implements equals/hashcode, not the nested entity class.
Steps to Reproduce:
1. open session and fetch object using composite-id
2. open new session and fetch same object again using different instance of composite-id but with same identity
Invalid Postconditions: On second retrieve, Hibernate fails to get the object from the cache and unnecessarily reloads the object. CachKeys containing different instances of the composite-id always fail to be equal even though they have the same persistent identity.
Attachment Contents
Code fix is attached as well as a Junit test case that reproduces the problem and validates the fix. The full Hibernate suite was also executed with no impact.
Attachment contains:
New Test Method:
org.hibernate.test.cache.BaseCacheProviderTestCase.testQueryCacheComplexItem
New Test Entity Items:
org\hibernate\test\cache\ComplexItem.hbm.xml
org.hibernate.test.cache.ComplexItem
org.hibernate.test.cache.ComplexItemPK
Code Fix:
org.hibernate.cache.CacheKey (see FIX comments)
Problem and Fix Details
Hibernate generally strives to use persistent identifiers for managing object identity rather than the equals/hashcode methods implemented by entity classes. While it is good practice to implement equals/hashcode, Hibernate does not generally force users to do this.
When wrapping a composite-id object, the current implementation of CacheKey fails to recurse through nested complex entities to query for equality based on persistent identity. Instead, when the recursion algorithm hits a complex entity, it invokes equals directly on that entity rather than further recursing through the identifier object.
Notably, the recursion logic for equals is not symmetrical with the recursion logic for hashcode, which does recurse through identifier objects. So, while CacheKey never invokes hashcode on nested complex entities, it does invoke equals on these entities.
A simple fix to this inconsistency is to store the factory parameter passed to CacheKey and later pass that parameter to the overloaded method:
Type.isEqual(Object x, Object y, EntityMode entityMode, SessionFactoryImplementor factory).
This fix restores symmetry to equals and hashcode behavior. By calling this overloaded method, the thread of execution will enter EntityType. isEqual(Object x, Object y, EntityMode entityMode, SessionFactoryImplementor factory), which correctly recurses through complex identifiers.
Design Principles
Hibernate should strive to behave predictably even in scenarios where users do not follow best practices.
Hibernate should strive to be as forgiving as possible as long there is no negative consequence caused by such forgiveness.
Hibernate should behave as consistently as possible. If Hibernate does not generally rely user-implemented equals/hashcode, it is best to avoid exceptions to this rule wherever possible.
Possible Future Enhancement
Mapping composite-ids that contain complex entities can cause deep object graphs to be cached as part of CacheKey. This is unsettling because of it's potential to consume memory unnecessarily and unpredictably.
Currently, CacheKey caches the hashcode by recursing through a complex graph of identifier objects. Perhaps, it would also be possible for CacheKey to cache an object graph of identifier objects whose leaves hold primitive values. This would further add symmetry between hashcode and equals and lighten the load for caching composite-ids that hold entity classes.
Robustly supporting composite-ids that hold complex identifiers seems like a worthwhile design goal.
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15 years
[Hibernate-JIRA] Created: (HHH-1985) NodeTraverser is not SOE-safe
by Sergey Vladimirov (JIRA)
NodeTraverser is not SOE-safe
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Key: HHH-1985
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1985
Project: Hibernate3
Type: Improvement
Components: core
Versions: 3.2.0.cr3
Reporter: Sergey Vladimirov
Priority: Minor
org.hibernate.hql.ast.util.NodeTraverser
It is possible for java.lang.StackOverflowError to occur in NodeTraverser.java:41;42 with very deep tree. Need another algorith to visit whole tree.
08.08 19:50:09 ERROR [ArpSiteServlet] Servlet.service() for servlet ArpSiteServlet threw exception
java.lang.StackOverflowError
at org.hibernate.hql.ast.util.NodeTraverser.visitDepthFirst(NodeTraverser.java:41)
at org.hibernate.hql.ast.util.NodeTraverser.visitDepthFirst(NodeTraverser.java:41)
at org.hibernate.hql.ast.util.NodeTraverser.visitDepthFirst(NodeTraverser.java:42)
at org.hibernate.hql.ast.util.NodeTraverser.visitDepthFirst(NodeTraverser.java:42)
at org.hibernate.hql.ast.util.NodeTraverser.visitDepthFirst(NodeTraverser.java:42)
at org.hibernate.hql.ast.util.NodeTraverser.visitDepthFirst(NodeTraverser.java:42)
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15 years, 1 month