Fix for http://issues.alfresco.com/jira/browse/ALF-713.

Can't reproduce the bug but spotted a race condition in UserUsageTrackingComponent that may cause this in rare circumstances. Deal with this by throwing a ConcurrencyFailureException and let the txn retry handler retry the operation.

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@19862 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/domain/UsageDeltaDAO.java

@@ -43,6 +43,14 @@ public interface UsageDeltaDAO
      */
     public long getTotalDeltaSize(NodeRef usageNodeRef);
     
+    /**
+     * Get the total delta size for a node and remove any deltas used in the calculation.
+     * 
+     * @param nodeRef       the node reference
+     * @return              sum of delta sizes (in bytes) - can be +ve or -ve
+     */
+    public long getAndRemoveTotalDeltaSize(NodeRef usageNodeRef);
+
     public Set<NodeRef> getUsageDeltaNodes();
     
     public int deleteDeltas(NodeRef nodeRef);

source/java/org/alfresco/repo/domain/hibernate/HibernateUsageDeltaDAO.java

@@ -31,6 +31,7 @@ import org.alfresco.service.cmr.repository.InvalidNodeRefException;
 import org.alfresco.service.cmr.repository.NodeRef;
 import org.alfresco.util.GUID;
 import org.alfresco.util.Pair;
+import org.springframework.dao.ConcurrencyFailureException;
 import org.springframework.extensions.surf.util.ParameterCheck;
 import org.hibernate.Query;
 import org.hibernate.Session;
@@ -158,12 +159,12 @@ public class HibernateUsageDeltaDAO extends HibernateDaoSupport implements Usage
         
         // execute
         Integer delCount = (Integer) getHibernateTemplate().execute(callback);
-        
-        return delCount.intValue();
+
+        return (delCount == null ? 0 : delCount.intValue());
     }
     
     @SuppressWarnings("unchecked")
-    public long getTotalDeltaSize(NodeRef nodeRef)
+    private Object[] getTotalDeltaSizeImpl(NodeRef nodeRef)
     {
         final Long nodeId = getNodeIdNotNull(nodeRef);
         HibernateCallback callback = new HibernateCallback()
@@ -176,10 +177,40 @@ public class HibernateUsageDeltaDAO extends HibernateDaoSupport implements Usage
                 return query.uniqueResult();
             }
         };
+
         // execute read-only tx
-        Long queryResult = (Long)getHibernateTemplate().execute(callback);
-       
-        return (queryResult == null ? 0 : queryResult);
+        return (Object[])getHibernateTemplate().execute(callback);
+    }
+
+    public long getTotalDeltaSize(NodeRef nodeRef)
+    {
+        Object[] result = getTotalDeltaSizeImpl(nodeRef);
+        Long queryResult = (Long)result[1];
+        return (queryResult == null ? 0 : queryResult.longValue());
+    }
+
+    /**
+     * Guard against deleting deltas committed by another transaction after calculating the delta sum above.
+	 * If the expected number of deletes is different from the actual number of deletes then deltas from
+	 * another committed transaction are probably being removed.
+	 */
+    @SuppressWarnings("unchecked")
+    public long getAndRemoveTotalDeltaSize(NodeRef nodeRef)
+    {
+        Object[] result = getTotalDeltaSizeImpl(nodeRef);
+        Long queryResult = (Long)result[1];
+        Number deltaCount = (Number)result[0];
+
+        long expectedNumDeletes = deltaCount == null ? 0 : deltaCount.intValue();
+
+        int numDeltasRemoved = deleteDeltas(nodeRef);
+
+        if(expectedNumDeletes != numDeltasRemoved) {
+            throw new ConcurrencyFailureException("More than expected number of usage delta deletes has occurred for node id "
+                    + nodeRef.getId() + " in store " + nodeRef.getStoreRef());
+        }
+
+        return (queryResult == null ? 0 : queryResult.longValue());
     }
     
     public void insertDelta(NodeRef usageNodeRef, long deltaSize)

source/java/org/alfresco/repo/domain/hibernate/UsageDelta.hbm.xml

@@ -50,7 +50,7 @@
     <!-- Get total usage delta for a node -->
     <query name="usage.GetTotalDeltaSize">
         select
-            sum(deltaSize)
+            count(deltaSize), sum(deltaSize)
         from
             org.alfresco.repo.domain.hibernate.UsageDeltaImpl as usage_delta
         where

source/java/org/alfresco/repo/usage/ContentUsageImpl.java

@@ -504,7 +504,11 @@ public class ContentUsageImpl implements ContentUsageService,
         return (currentUsage == null ? -1 : currentUsage);
     }
     
-    public long getUserUsage(String userName)
+    public long getUserUsage(String userName) {
+        return getUserUsage(userName, false);
+    }
+    
+    public long getUserUsage(String userName, boolean removeDeltas)
     {
         ParameterCheck.mandatoryString("userName", userName);
         
@@ -518,9 +522,11 @@ public class ContentUsageImpl implements ContentUsageService,
         
         if (currentUsage != -1)
         {
-            // add any deltas
-            currentUsage = currentUsage + usageService.getTotalDeltaSize(personNodeRef);
-            
+            long deltaSize = removeDeltas ? usageService.getAndRemoveTotalDeltaSize(personNodeRef) :
+                usageService.getTotalDeltaSize(personNodeRef);
+            // add any deltas to the currentUsage, removing them if required
+            currentUsage = currentUsage + deltaSize;
+
             if (currentUsage < 0)
             {
                 if (logger.isWarnEnabled())

source/java/org/alfresco/repo/usage/UsageServiceImpl.java

@@ -49,6 +49,11 @@ public class UsageServiceImpl implements UsageService
         return usageDeltaDAO.getTotalDeltaSize(usageNodeRef);
     }
     
+    public long getAndRemoveTotalDeltaSize(NodeRef usageNodeRef)
+    {
+        return usageDeltaDAO.getAndRemoveTotalDeltaSize(usageNodeRef);
+    }
+    
     public Set<NodeRef> getUsageDeltaNodes()
     {
         return usageDeltaDAO.getUsageDeltaNodes();

source/java/org/alfresco/repo/usage/UserUsageTrackingComponent.java

@@ -564,9 +564,11 @@ public class UserUsageTrackingComponent extends AbstractLifecycleBean
                     long currentUsage = contentUsageImpl.getUserStoredUsage(personNodeRef);
                     if (currentUsage != -1)
                     {
-                        // collapse the usage deltas
-                        currentUsage = contentUsageImpl.getUserUsage(userName);
-                        usageService.deleteDeltas(personNodeRef);
+                    	// Collapse the usage deltas
+                        // Calculate and remove deltas in one go to guard against deletion of
+                        // deltas from another transaction that have not been included in the
+                        // calculation
+                        currentUsage = contentUsageImpl.getUserUsage(userName, true);
                         contentUsageImpl.setUserStoredUsage(personNodeRef, currentUsage);
                         
                         if (logger.isTraceEnabled()) 

source/java/org/alfresco/service/cmr/usage/UsageService.java

@@ -44,7 +44,13 @@ public interface UsageService
      */
     @NotAuditable
     public long getTotalDeltaSize(NodeRef usageNodeRef);
-    
+
+    /**
+     * Get sum of usage delta sizes and remove affected deltas.
+     */
+    @NotAuditable
+    public long getAndRemoveTotalDeltaSize(NodeRef usageNodeRef);
+
     /**
      * Get distinct set of usage delta nodes
      */