[hibernate-dev] Multiple joined-subclass mappings to same table
Hi, I am bit puzzled with this. I am looking at a codebase, where there are multiple joined-subclass mappings (in separate hbm.xml files) which map to same table. For union-subclass, we correctly get exception for duplicate mapping. But for joined-subclass it allows multiple mappings to same table. In the hibernate source code, I see that for Joined subclass, the table mapping is added with following method call. Table mytable = mappings.addTable( schema, catalog, getClassTableName( joinedSubclass, node, schema, catalog, null, mappings ), getSubselect( node ), false For union-subclass, the mapping gets added with Table mytable = mappings.addDenormalizedTable( schema, catalog, getClassTableName(unionSubclass, node, schema, catalog, denormalizedSuperTable, mappings ), unionSubclass.isAbstract() != null && unionSubclass.isAbstract(), getSubselect( node ), denormalizedSuperTable ); mappings.addTable doesnt throw exception if the table mapping already exists. Is the behaviour for joined subclass by design? Because I see this fact being used in some projects, where to extend an already created joined-subclass, a new hibernate-config file is added with joined-subclass definition duplicated, with additional attributes (and columns) added to existing table. So essentially, you have two joined-subclass definitions, mapping two separate entities to same table. This does look like using some loop hole in the code? Thanks, Unmesh ___ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
[hibernate-dev] large hql queries holding classloader lock for too long in weblogic
Hi, We had an issue in our project where large hql expressions holding on lock to ChangeAwareClassloader in weblogic. We had an hql query which was like select * from ClassA a where a.identifier = 'id1' or a.identifier='id2' or . a.identifier='id1000'. This was certainly bad to have this big or expression, but an issue this caused in weblogic is something interesting. Hibernate query engine processes each identifier in a query to see if its a Java Class. So for each one of ClassA, a.identifier etc it calls Class.forName, if NoClassDefFound exception is thrown, ReflectHelper.getConstantValue returns null. Now the problem is, if the expression is huge, recursive calls to /NodeTraverser.visitDepthFirst create huge stack trace. While building ClassNotFoundException, system class loader gets stuck to build all this stack trace. Because weblogic/utils/classloaders/ChangeAwareClassLoader.loadClass method is synchronized, any other thread trying to load any other class is blocked. If the stack trace is huge and taking consideratble amount of time to create Exception object, the lock is held for that much time, blocking every other thread trying to any the class. It brought down our servers in test environment. Is this a known issue in weblogic and hibernate? I know that building such a large expression is bad(and we have already changed the code which was doing that), but the way its blocking the classloader in weblogic is an issue I think. Following is the thread dump. "[STUCK] ExecuteThread: '9' for queue: 'weblogic.kernel.Default (self-tuning)'" id=614 idx=0x3f8 tid=15385 prio=1 alive, in native, daemon at pthread_cond_wait@@GLIBC_2.3.2+170(:0)@0x318c008a7a at vmtWaitUntilNotSoftSuspended+66(:0)@0x2a955e35c2 at find_codeinfo+138(:0)@0x2a955b032e at cmFindStackCodeInfoWithHint+44(:0)@0x2a955b040e at frameIterFindCodeInfo+19(:0)@0x2a9571b11f at frameIterGetCurrentAndStep+130(:0)@0x2a9571b489 at jniFillInStackTrace+368(:0)@0x2a95630d25 at JVM_FillInStackTrace+9(:0)@0x2a95647661 at RJNI_jrockit_vm_Reflect_fillInStackTrace0+9(:0)@0x2a956f5983 at jrockit/vm/Reflect.fillInStackTrace0(Ljava/lang/Throwable;)V(Native Method) at java/lang/Throwable.fillInStackTrace()Ljava/lang/Throwable;(Native Method)[optimized] at java/lang/Throwable.(Throwable.java:218)[optimized] at java/lang/Exception.(Exception.java:59)[inlined] at java/lang/ClassNotFoundException.(ClassNotFoundException.java:65)[optimized] at java/net/URLClassLoader$1.run(URLClassLoader.java:200)[inlined] at jrockit/vm/AccessController.doPrivileged(AccessController.java:255)[inlined] at java/net/URLClassLoader.findClass(URLClassLoader.java:188)[optimized] at java/lang/ClassLoader.loadClass(ClassLoader.java:306)[optimized] ^-- Holding lock: java/net/urlclassloa...@0x4993580[thin lock] at java/lang/ClassLoader.loadClass(ClassLoader.java:299)[optimized] ^-- Holding lock: weblogic/utils/classloaders/genericclassloa...@0x469e900[thin lock] at java/lang/ClassLoader.loadClass(ClassLoader.java:251)[inlined] at weblogic/utils/classloaders/GenericClassLoader.loadClass(GenericClassLoader.java:158)[optimized] at weblogic/utils/classloaders/FilteringClassLoader.findClass(FilteringClassLoader.java:83)[inlined] at weblogic/utils/classloaders/FilteringClassLoader.loadClass(FilteringClassLoader.java:68)[optimized] at java/lang/ClassLoader.loadClass(ClassLoader.java:299)[optimized] ^-- Holding lock: weblogic/utils/classloaders/genericclassloa...@0x4969138[thin lock] at java/lang/ClassLoader.loadClass(ClassLoader.java:299)[inlined] at java/lang/ClassLoader.loadClass(ClassLoader.java:251)[inlined] at weblogic/utils/classloaders/GenericClassLoader.loadClass(GenericClassLoader.java:158)[inlined] at weblogic/utils/classloaders/ChangeAwareClassLoader.loadClass(ChangeAwareClassLoader.java:35)[optimized] ^-- Holding lock: weblogic/utils/classloaders/changeawareclassloa...@0x4915178[recursive] at jrockit/vm/Classes.loadClassInternal(Classes.java:75)[optimized] ^-- Holding lock: weblogic/utils/classloaders/changeawareclassloa...@0x4915178[fat lock] at jrockit/vm/RNI.c2java(J)V(Native Method) at jrockit/vm/Classes.forName0(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;(Native Method) at jrockit/vm/Classes.forName(Classes.java:125)[inlined] at java/lang/Class.forName(Class.java:164)[inlined] at org/hibernate/util/ReflectHelper.classForName(ReflectHelper.java:100)[inlined] at org/hibernate/util/ReflectHelper.getConstantValue(ReflectHelper.java:122)[inlined] at org/hibernate/hql/ast/QueryTranslatorImpl$JavaConstantConverter.handleDotStructure(QueryTranslatorImpl.java:569)[inlined] at org/hibernate/hql/ast/QueryTranslatorImpl$JavaConstantConverter.visit(QueryTranslatorImpl.java:564)[optimized] at org/hibernate/hql/ast/util/NodeTraverser.visi
[hibernate-dev] Why cglib was replaced with javassist?
hi, Till hibernate 3.2 cglib was default bytecode provider. why was it changed to javassist? thanks,unmesh _ Planning the weekend ? Here’s what is happening in your town. http://msn.asklaila.com/events/___ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
