private static void disableLlapCaching(HiveConf conf) {
      String llapIOETLSkipFormat = conf.getVar(HiveConf.ConfVars.LLAP_IO_ETL_SKIP_FORMAT);
      if (!"none".equals(llapIOETLSkipFormat)) {
        // Unless caching is explicitly required for ETL queries - disable it.
        conf.setVar(HiveConf.ConfVars.LLAP_IO_ETL_SKIP_FORMAT, "all");
      }
    }
Unless caching is explicitly required for ETL queries this method disables it.
LLAP cache content lookup is file based, and since compaction alters the file structure it is not beneficial to
cache anything here, as it won't (and actually can't) ever be looked up later.
@param conf the Hive configuration
ql/src/java/org/apache/hadoop/hive/ql/txn/compactor/QueryCompactor.java