Synchronized on database when unlock tables

h2/src/main/org/h2/engine/Session.java

@@ -923,6 +923,7 @@ public class Session extends SessionWithState {
             }
         }
         if (locks.size() > 0) {
+            synchronized (database) {
                 // don't use the enhanced for loop to save memory
                 for (int i = 0, size = locks.size(); i < size; i++) {
                     Table t = locks.get(i);
@@ -930,6 +931,7 @@ public class Session extends SessionWithState {
                 }
                 locks.clear();
             }
+        }
         savepoints = null;
         sessionStateChanged = true;
     }