diff --git a/src/main/java/org/caosdb/server/query/Query.java b/src/main/java/org/caosdb/server/query/Query.java
index d462a0b62683b4c838856b649f7afc2f0762727a..06345a9b784c505a57c5678b0c5ffe23973f850a 100644
--- a/src/main/java/org/caosdb/server/query/Query.java
+++ b/src/main/java/org/caosdb/server/query/Query.java
@@ -337,7 +337,8 @@ public class Query implements QueryInterface, ToElementable, TransactionInterfac
    * stored in the cache. This allows (some) cache entries to be shared among users since the final
    * check is applied after the retrieval of the result set from the cache (@see {@link
    * filterEntitiesWithoutRetrievePermission}) The cache is invalidated whenever there is a write
-   * operation (@see {@link writeTODO}).
+   * operation (@see {@link writeTODO}) TODO replace writeTODO and describe how invalidation is
+   * done.
    */
   private static ICacheAccess<String, Serializable> cache =
       Cache.getCache("HIGH_LEVEL_QUERY_CACHE");
@@ -418,9 +419,9 @@ public class Query implements QueryInterface, ToElementable, TransactionInterfac
 
   /**
    * @return The result set table name.
-   * @throws TransactionException
+   * @throws QueryException
    */
-  private String sourceStrategy(final String sourceSet) throws TransactionException {
+  private String sourceStrategy(final String sourceSet) throws QueryException {
     try {
       this.sourceSet = sourceSet;
       initResultSetWithNameIDAndChildren();
@@ -441,7 +442,7 @@ public class Query implements QueryInterface, ToElementable, TransactionInterfac
       return this.sourceSet;
     } catch (final SQLException e) {
       e.printStackTrace();
-      throw new TransactionException(e);
+      throw new QueryException(e);
     }
   }
 
@@ -1158,7 +1159,8 @@ public class Query implements QueryInterface, ToElementable, TransactionInterfac
       String principal_desc =
           ((Principal) this.user.getPrincipal()).getUsername()
               + Principal.REALM_SEPARATOR
-              + ((Principal) this.user.getPrincipal()).getRealm();
+              + ((Principal) this.user.getPrincipal()).getRealm()
+              + Principal.REALM_SEPARATOR;
       sb.append(principal_desc);
     }
     if (this.versioned) {