@Override
          public Void run() throws Exception {
            runGetSplitsSync(splitFuturesRef, splitsRef, ugi);
            return null;
          }
ETL strategy is used when spending little more time in split generation is acceptable
(split generation reads and caches file footers).
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcInputFormat.java