@Override
  public void dropWMMapping(WMMapping mapping)
      throws NoSuchObjectException, InvalidOperationException, MetaException {
    String entityType = mapping.getEntityType().trim().toUpperCase();
    String entityName = normalizeIdentifier(mapping.getEntityName());
    boolean commited = false;
    Query query = null;
    try {
      openTransaction();
      MWMResourcePlan resourcePlan = getMWMResourcePlan(
          mapping.getResourcePlanName(), mapping.getNs(), true);
      query = pm.newQuery(MWMMapping.class,
          "resourcePlan == rp && entityType == type && entityName == name");
      query.declareParameters("MWMResourcePlan rp, java.lang.String type, java.lang.String name");
      if (query.deletePersistentAll(resourcePlan, entityType, entityName) != 1) {
        throw new NoSuchObjectException("Cannot delete mapping.");
      }
      commited = commitTransaction();
    } finally {
      rollbackAndCleanup(commited, query);
    }
  }
This is a cleanup method which is used to rollback a active transaction
if the success flag is false and close the associated Query object. This method is used
internally and visible for testing purposes only
@param success Rollback the current active transaction if false
@param query Query object which needs to be closed
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java