4. Out of Memory Error 발생
resampling, pandas chunk, map, concat 등의노오력을하면어떻게든읽을
수는있겠지만, 전처리까지하려면한참걸린다...
5. Apache Spark
https://spark.apache.org/
Spark is a fast and general engine for large‑scale data processing
Apache Spark has an advanced DAG execution engine that
supports acyclic data flow and in‑memory computing