Parquet_with_Spark

Parquet Benfits:
===============
- Columnar storage
- Efficient storage
- Efficient data IO and cpu utilisation.
- Reads less no:of blocks
- Key concepts
  Block size
  Row Group - columns data
  page
- Parquet uses default compression as GZIP



Save & write as parquet:
========================
df.save.parquet("path_to_save")
df.read.parquet("path_to_read")

Params:
=======
Change block size: Use parquet.block.size
size of the block and row group dictates overall performance.