We've re-jigged the tables to allow a faster query to be executed, and are now executing what should be two fast queries rather than a single slow one. Not great in terms of network traffic, but we're trusting Hibernate to do sensible things with database connections.
We've had to go to native SQL for the first query, but it's now a couple of orders of magnitude faster with the size of data sets that we're testing with. We've encountered a different problem however.
The old, slow query code looked like this:
Code:
List warehouseItems = hibernateTemplate.findByNamedQueryAndNamedParam(WarehouseItemDTO.class.getName()
+ ".query.findByIDWorkspace", new String[] { "id", "workspaceName" }, new Object[] {
Integer.valueOf((int) id), workspace });
if (warehouseItems.size() > 1) {
// UUID and workspace together form a composite primary key so we only expect one record to be returned
log.warn("More than one record returned for id '" + id + "' and workspace '" + workspace
+ "' - check table integrity");
}
WarehouseItem warehouseItem = null;
if (warehouseItems.size() > 0) {
warehouseItem = (WarehouseItem) warehouseItems.get(0);
}
return warehouseItem;
The new, faster version looks like this:
Code:
WarehouseItemDTO warehouseItem = (WarehouseItemDTO) hibernateTemplate.execute(new HibernateCallback() {
/**
* {@inheritDoc}
*/
public Object doInHibernate(Session session) throws HibernateException, SQLException {
SQLQuery sqlQuery = session.createSQLQuery("SELECT ID FROM WHNODE WHERE "
+ "NEWID = :newid AND WORKSPACE = :workspace");
sqlQuery.setInteger("newid", (int) id);
sqlQuery.setString("workspace", workspace);
List warehouseNodeIds = sqlQuery.list();
if (warehouseNodeIds.size() > 1) {
/*
* newid and workspace together form a composite primary key so we only expect one record to be
* returned
*/
log.warn("More than one record returned for id '" + id + "' and workspace '" + workspace
+ "' - check table integrity");
}
WarehouseItemDTO result = null;
if (!warehouseNodeIds.isEmpty()) {
result = (WarehouseItemDTO) session.load(itemClass, (Integer) warehouseNodeIds.get(0));
}
return result;
}
});
return warehouseItem;
The problem with this approach is that after a period of time, we start getting the following problem
Code:
java.lang.ExceptionInInitializerError
at org.hibernate.engine.StatefulPersistenceContext.getCollectionLoadContext(StatefulPersistenceContext.java:146)
at org.hibernate.type.CollectionType.getCollection(CollectionType.java:488)
at org.hibernate.type.CollectionType.resolveKey(CollectionType.java:341)
at org.hibernate.type.CollectionType.resolve(CollectionType.java:335)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:116)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:842)
at org.hibernate.loader.Loader.doQuery(Loader.java:717)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1785)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:47)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:41)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:2730)
at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:365)
at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:346)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:123)
at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:161)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:87)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:862)
at org.hibernate.impl.SessionImpl.load(SessionImpl.java:781)
at org.hibernate.impl.SessionImpl.load(SessionImpl.java:774)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.orm.hibernate3.HibernateTemplate$CloseSuppressingInvocationHandler.invoke(HibernateTemplate.java:1197)
at $Proxy21.load(Unknown Source)
at com.example.module.warehouse.dao.WarehouseItemDAOImpl$1.doInHibernate(WarehouseItemDAOImpl.java:175)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:367)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:333)
at com.example.module.warehouse.dao.WarehouseItemDAOImpl.getWarehouseItemByID(WarehouseItemDAOImpl.java:148)
at com.example.module.warehouse.WarehouseSynchronizerImpl.synchronize(WarehouseSynchronizerImpl.java:94)
at com.example.module.warehouse.WarehouseSynchronizerImpl.synchronize(WarehouseSynchronizerImpl.java:67)
at com.example.module.warehouse.WarehouseEventListener$1.doInJcr(WarehouseEventListener.java:129)
at com.example.module.springmodule.MIQJcrTemplate.doExecute(MIQJcrTemplate.java:125)
at com.example.module.springmodule.MIQJcrTemplate.execute(MIQJcrTemplate.java:101)
at com.example.module.warehouse.WarehouseEventListener.processInterestingPaths(WarehouseEventListener.java:160)
at com.example.module.warehouse.WarehouseEventListener.onEvent(WarehouseEventListener.java:102)
at org.apache.jackrabbit.core.observation.EventConsumer.consumeEvents(EventConsumer.java:231)
at org.apache.jackrabbit.core.observation.ObservationDispatcher.run(ObservationDispatcher.java:145)
at java.lang.Thread.run(Thread.java:619)
Caused by: org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: java.lang.ThreadDeath (Caused by java.lang.ThreadDeath) (Caused by org.apache.commons.logging.LogConfigurationException: java.lang.ThreadDeath (Caused by java.lang.ThreadDeath))
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:543)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
at org.hibernate.engine.CollectionLoadContext.<clinit>(CollectionLoadContext.java:31)
... 40 more
Caused by: org.apache.commons.logging.LogConfigurationException: java.lang.ThreadDeath (Caused by java.lang.ThreadDeath)
at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:397)
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
... 44 more
Caused by: java.lang.ThreadDeath
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1229)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1189)
at org.apache.commons.logging.impl.LogFactoryImpl$1.run(LogFactoryImpl.java:441)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.commons.logging.impl.LogFactoryImpl.loadClass(LogFactoryImpl.java:435)
at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:376)
... 45 more
Subsequent calls to that method then throw NoClassDefFoundError, since the JVM marks the class as unusable after getting the ExceptionInInitializerError.
This is using Java 5 and Java 6 on Windows Vista and Fedora Core 6, both running Tomcat 5.0.30. I'm going to try some other Tomcat versions and see whether it's some strange container interaction.
No webapp is being deployed or undeployed to Tomcat during the period that the error occurs, and I haven't yet discovered why the ThreadDeath error is happening. Obviously, the faster method listed above isn't a good solution for us going forward, since the web app requires reloading to dispose of the classloader with the bad reference.
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