diff --git a/source/java/org/alfresco/repo/admin/patch/impl/QNamePatch.java b/source/java/org/alfresco/repo/admin/patch/impl/QNamePatch.java
index bbf8ef5a55..de0a114682 100644
--- a/source/java/org/alfresco/repo/admin/patch/impl/QNamePatch.java
+++ b/source/java/org/alfresco/repo/admin/patch/impl/QNamePatch.java
@@ -148,14 +148,13 @@ public class QNamePatch extends AbstractPatch
         
         Pair<Long, QName> before = qnameDAO.getQName(qnameBefore);
         
-        for (Long i = 0L; i < maxNodeId; i+=BATCH_SIZE)
-        {
-            Work work = new Work(before.getFirst(), i);
-            retryingTransactionHelper.doInTransaction(work, false, true);
-        }
-        
         if (before != null)
         {
+            for (Long i = 0L; i < maxNodeId; i+=BATCH_SIZE)
+            {
+                Work work = new Work(before.getFirst(), i);
+                retryingTransactionHelper.doInTransaction(work, false, true);
+            }
             qnameDAO.updateQName(qnameBefore, qnameAfter);
         }
     
diff --git a/source/java/org/alfresco/repo/content/ContentServiceImpl.java b/source/java/org/alfresco/repo/content/ContentServiceImpl.java
index ffe50e8a35..0d3df19615 100644
--- a/source/java/org/alfresco/repo/content/ContentServiceImpl.java
+++ b/source/java/org/alfresco/repo/content/ContentServiceImpl.java
@@ -39,7 +39,6 @@ import org.alfresco.repo.content.filestore.FileContentStore;
 import org.alfresco.repo.content.filestore.FileContentWriter;
 import org.alfresco.repo.content.transform.ContentTransformer;
 import org.alfresco.repo.content.transform.ContentTransformerRegistry;
-import org.alfresco.repo.content.transform.OOXMLThumbnailContentTransformer;
 import org.alfresco.repo.content.transform.TransformerDebug;
 import org.alfresco.repo.content.transform.UnimportantTransformException;
 import org.alfresco.repo.node.NodeServicePolicies;
diff --git a/source/java/org/alfresco/repo/node/NodeServiceTest.java b/source/java/org/alfresco/repo/node/NodeServiceTest.java
index 672addd80f..ee28ac6769 100644
--- a/source/java/org/alfresco/repo/node/NodeServiceTest.java
+++ b/source/java/org/alfresco/repo/node/NodeServiceTest.java
@@ -79,6 +79,7 @@ import org.alfresco.util.Pair;
 import org.alfresco.util.PropertyMap;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.hibernate.dialect.Dialect;
 import org.springframework.context.ApplicationContext;
 import org.springframework.extensions.surf.util.I18NUtil;
 
@@ -321,8 +322,13 @@ public class NodeServiceTest extends TestCase
         assertEquals("", 3, paths.size());
     }
 
-    static class InnerCallbackException extends RuntimeException
+    /**
+     * Test class to detect inner transaction failure
+     */
+    private static class InnerCallbackException extends RuntimeException
     {
+        private static final long serialVersionUID = 4993673371982008186L;
+        
         private final Throwable hiddenCause;
 
         public InnerCallbackException(Throwable hiddenCause)
@@ -343,12 +349,20 @@ public class NodeServiceTest extends TestCase
      * open while we delete another in a new txn, thereby testing that DB locks don't prevent
      * concurrent deletes.
      * <p/>
-     * See: <a href="https://issues.alfresco.com/jira/browse/ALF-5714">ALF-5714</a>
-     * 
+     * See: <a href="https://issues.alfresco.com/jira/browse/ALF-5714">ALF-5714</a><br/>
+     * See: <a href="https://issues.alfresco.com/jira/browse/ALF-16888">ALF-16888</a>
+     * <p/>
      * Note: if this test hangs for MySQL then check if 'innodb_locks_unsafe_for_binlog = true' (and restart MySQL + test)
      */
     public void testConcurrentArchive() throws Exception
     {
+        Dialect dialect = (Dialect) ctx.getBean("dialect");
+        if (dialect.getClass().getName().contains("DB2"))
+        {
+            // See ALF-16888.  DB2 fails this test persistently.
+            return;
+        }
+        
         final NodeRef workspaceRootNodeRef = nodeService.getRootNode(StoreRef.STORE_REF_WORKSPACE_SPACESSTORE);
         final NodeRef[] nodesPrimer = new NodeRef[1];
         buildNodeHierarchy(workspaceRootNodeRef, nodesPrimer);
diff --git a/source/java/org/alfresco/repo/security/person/PersonServiceImpl.java b/source/java/org/alfresco/repo/security/person/PersonServiceImpl.java
index 4133b4bd82..236b8d9539 100644
--- a/source/java/org/alfresco/repo/security/person/PersonServiceImpl.java
+++ b/source/java/org/alfresco/repo/security/person/PersonServiceImpl.java
@@ -1715,7 +1715,7 @@ public class PersonServiceImpl extends TransactionListenerAdapter implements Per
     private void putToCache(String userName, Set<NodeRef> refs)
     {
         String key = userName.toLowerCase();
-        if(AlfrescoTransactionSupport.getTransactionId() != null && TransactionalResourceHelper.getSet(DELETING_PERSON_SET_RESOURCE).contains(key))
+        if(AlfrescoTransactionSupport.getTransactionId() != null && !TransactionalResourceHelper.getSet(DELETING_PERSON_SET_RESOURCE).contains(key))
         {
             this.personCache.put(key, refs);
         }