throws HiveException {
// merge work only needs input and output.
MergeWork mergeWork = new MergeWork(mergeFilesDesc.getInputDir(),
mergeFilesDesc.getOutputDir());
mergeWork.setListBucketingCtx(mergeFilesDesc.getLbCtx());
mergeWork.resolveConcatenateMerge(db.getConf());
mergeWork.setMapperCannotSpanPartns(true);
DriverContext driverCxt = new DriverContext();
BlockMergeTask taskExec = new BlockMergeTask();
taskExec.initialize(db.getConf(), null, driverCxt);
taskExec.setWork(mergeWork);