private static int getQueueVar(ConfVars var, JobConf jobConf, Configuration daemonConf) {
    // Check job config for overrides, otherwise use the default server value.
    int jobVal = jobConf.getInt(var.varname, -1);
    return (jobVal != -1) ? jobVal : HiveConf.getIntVar(daemonConf, var);
  }
Creates the record reader and checks the input-specific compatibility.
@return The reader if the split can be read, null otherwise.
llap-server/src/java/org/apache/hadoop/hive/llap/io/api/impl/LlapRecordReader.java