[hibernate-issues] [Hibernate-JIRA] Created: (HHH-2503) AbstractEntityPersister swallows JDBCExceptions in processGeneratedProperties

[Dag Liodden (JIRA)]

AbstractEntityPersister swallows JDBCExceptions in processGeneratedProperties
-----------------------------------------------------------------------------

         Key: HHH-2503
         URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2503
     Project: Hibernate3
        Type: Bug

  Components: core  
    Versions: 3.2.1, 3.2.2, 3.2.3    
 Environment: 3.2.2GA and trunk
    Reporter: Dag Liodden


Seems to be a small typo on line 3718 in AbstractEntityPersister (trunk and 3.2.2 GA) which makes exceptions during property generation being logged but not thrown:

      
 catch( SQLException sqle ) {
         JDBCExceptionHelper.convert(
               getFactory().getSQLExceptionConverter(),
               sqle,
               "unable to select generated column values",
               selectionSQL
         );


There should be a throw in there I guess. :)

      
 catch( SQLException sqle ) {
         throw JDBCExceptionHelper.convert(
               getFactory().getSQLExceptionConverter(),
               sqle,
               "unable to select generated column values",
               selectionSQL
         );

This bug will not be noticeable in most cases and is probably why it hasn't been detected / fixed so far. The method in question (processGeneratedProperties) is used for retrieving properties that are marked as "generated" in the mapping document / annotations - in other words any value that the database provides and is considered "read-only" from the Hibernate application's point of view.

The generated value is retrieved by an extra select statement executed by Hibernate after an entity has been inserterd and / or updated (according to how the generated property is flagged). In my particular case, a property (not a key) is marked as generated="insert", so after Hibernate inserts a new entity to the database, it will immediately do a select and set the generated property to the value the database returns.

Only in rare cases will this select fail in any way - in fact, I cannot think of any situations other than mapping errors (e.g getInt on a CHAR column) that can cause errors in this last select. That is in addition to my situation - a deadlock.

My entity class uses uuid.hex generator for the PK, but at one point, we introduced a second unique key due to purely aestethic reasons. This is a SQL Server identity column. Since we don't do any explicit table locking during the inserts, we end up with deadlocks every time the following happens:


T1: INSERT INTO TABLE (ID) values (?)
T2: INSERT INTO TABLE (ID) values (?)
T2: SELECT GENERATED_ID FROM TABLE WHERE ID = ? -- T1's insert hasn't been committed, so what should the the generated ID be? Deadlock!
T1: SELECT GENERATED_ID FROM TABLE WHERE ID = ?
...


SQL Server throws an error to indicate the deadlock, but due to the missing throw in the processGeneratedProperties-method, it is never shown to the process doing the insert. The generated property is not set and retains it's null (or 0 in case of a primitive) without the business logic ever knowing that the entity could not be saved. 

-- 
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