public static boolean isExclusiveCTASEnabled(Configuration conf) {
    return HiveConf.getBoolVar(conf, ConfVars.TXN_CTAS_X_LOCK);
  }
For any insert/updates set dir cache to read-only mode, where it wouldn't
add any new entry to cache.
When updates are executed, delta folders are created only at the end of the statement
and at the time of acquiring locks, there would not be any delta folders. This can cause wrong data to be reported
when "insert" followed by "update" statements are executed. In such cases, use the cache as read only mode.
ql/src/java/org/apache/hadoop/hive/ql/io/AcidUtils.java