@Explain(displayName = "update creation metadata", displayOnlyOnTrue = true,
      explainLevels = { Level.USER, Level.DEFAULT, Level.EXTENDED })
  public boolean isUpdateCreationMetadata() {
    return updateCreationMetadata;
  }
DDL task description of updating a materialized view.
ql/src/java/org/apache/hadoop/hive/ql/ddl/view/materialized/update/MaterializedViewUpdateDesc.java