title: spark.sql.cbo.enabled=true with Hive table
body: <p>In Spark 2.2 the Cost Based Optimizer option has been enabled. The documentation appears to be saying that we need to analyze the tables in Spark before enabling this option. I would like to know if this option is helpful when we have all the table data coming in from Hive as the Data storage layer. Since spark will read Hive using Hivetablescan (avoiding Map/Reduce) does it make sense to use CBO configuration when data is read from Hive.</p>