private void createPreInsertDesc(Table table, boolean overwrite) {
    PreInsertTableDesc preInsertTableDesc = new PreInsertTableDesc(table, overwrite);
    this.rootTasks
        .add(TaskFactory.get(new DDLWork(getInputs(), getOutputs(), preInsertTableDesc)));
  }
Merge stmt with early split update may create several (2) writes to the same
table with the same {@link WriteType}, e.g. if original Merge stmt has both update and
delete clauses, and update is split into insert + delete, in which case it's not an
error
ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java