[hibernate-issues] [Hibernate-JIRA] Updated: (HHH-5945) Race condition in building query cache

[Luca Domenichini (JIRA)]

     [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-5945?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Luca Domenichini updated HHH-5945:
----------------------------------

    Attachment: TestCase.zip

Eclipse project with test case attached.
This test case uses Hibernate 3.6.4, where I see the same exception as described before

> Race condition in building query cache
> --------------------------------------
>
>                 Key: HHH-5945
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-5945
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: caching (L2)
>    Affects Versions: 3.6.1
>         Environment: Hibernate 3.6.1, EhCache 2.3.0..2.3.2, MSSQL 2005 Developer Edition
>            Reporter: Luca Domenichini
>         Attachments: TestCase.zip
>
>   Original Estimate: 1h
>  Remaining Estimate: 1h
>
> I have this sample program that creates 10 threads that executes the same cached query in a thread-local current session context. Entity ClasseAltezza is a READ_ONLY cached entity.
> {panel}{noformat}
> 	public static void main(String[] args) {
> 		List<Thread> threads = new ArrayList<Thread>();
> 		for (int i=0; i<10; i++) {
> 			Thread t = new Thread() {
> 				@Override
> 				public void run() {
> 					try {
> 						HibernateUtil.beginTransaction();
> 						HibernateUtil.getCurrentSession()
> 							.createCriteria(ClasseAltezza.class)
> 							.setCacheable(true)
> 							.setCacheRegion(ClasseAltezza.class.toString())
> 							.list();
> 						HibernateUtil.commitTransaction();
> 					}
> 					catch (Exception ex) {
> 						ex.printStackTrace();
> 						HibernateUtil.rollbackTransaction();
> 					}
> 				}
> 			};
> 			threads.add(t);
> 		}
> 		for (Thread t : threads)
> 			t.start();
> 	}
> {noformat}{panel}
> This is the output:
> {panel}{noformat}org.hibernate.cache.CacheException: net.sf.ehcache.ObjectExistsException: Cache class com.promag.wms.base.persistence.entities.ClasseAltezza already exists
> 	at org.hibernate.cache.EhCacheProvider.buildCache(EhCacheProvider.java:101)
> 	at org.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge.buildQueryResultsRegion(RegionFactoryCacheProviderBridge.java:115)
> 	at org.hibernate.cache.StandardQueryCache.<init>(StandardQueryCache.java:78)
> 	at org.hibernate.cache.StandardQueryCacheFactory.getQueryCache(StandardQueryCacheFactory.java:44)
> 	at org.hibernate.impl.SessionFactoryImpl.getQueryCache(SessionFactoryImpl.java:1173)
> 	at org.hibernate.loader.Loader.listUsingQueryCache(Loader.java:2285)
> 	at org.hibernate.loader.Loader.list(Loader.java:2268)
> 	at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:119)
> 	at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1716)
> 	at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:347)
> 	at com.promag.wms.base.persistence.methods.ClasseAltezzaMethods.getAll(ClasseAltezzaMethods.java:30)
> 	at Test$1.run(Test.java:20)
> Caused by: net.sf.ehcache.ObjectExistsException: Cache class com.promag.wms.base.persistence.entities.ClasseAltezza already exists
> 	at net.sf.ehcache.CacheManager.addCache(CacheManager.java:888)
> 	at org.hibernate.cache.EhCacheProvider.buildCache(EhCacheProvider.java:94)
> 	... 11 more
> {noformat}{panel}
> I see that in Hibernate 3.6.0 there were a synchronized block in method SessionFactory.getQueryCache(String regionName) the prevented the same query region to be built twice as it happens in Hibernate 3.6.1, were the synchronized block is missing..
> This is the method in SessionFactoryImpl:
> {panel}{noformat}
> 	public QueryCache getQueryCache(String regionName) throws HibernateException {
> 		if ( regionName == null ) {
> 			return getQueryCache();
> 		}
> 		if ( !settings.isQueryCacheEnabled() ) {
> 			return null;
> 		}
> 		synchronized ( allCacheRegions ) { // THIS SYNCHRONIZED IS MISSING IN 3.6.1!!!!
> 			QueryCache currentQueryCache = ( QueryCache ) queryCaches.get( regionName );
> 			if ( currentQueryCache == null ) {
> 				currentQueryCache = settings.getQueryCacheFactory().getQueryCache( regionName, updateTimestampsCache, settings, properties );
> 				queryCaches.put( regionName, currentQueryCache );
> 				allCacheRegions.put( currentQueryCache.getRegion().getName(), currentQueryCache.getRegion() );
> 			}
> 			return currentQueryCache;
> 		}
> 	}
> {noformat}{panel}

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