title: Efficient way to read specific columns from parquet file in spark
body: <p>What is the  most efficient way to read only a subset of columns in spark from a parquet file that has many columns? Is using <code>spark.read.format("parquet").load(&lt;parquet&gt;).select(...col1, col2)</code> the best way to do that? I would also prefer to use typesafe dataset with case classes to pre-define my schema but not sure. </p>