Whether does it need to convert the objects in Row to internal representation, for example: java.lang.String to UTF8String java.lang.Decimal to Decimal
The internal representation is not stable across releases and thus data sources outside of Spark SQL should leave this as true.
Returns an estimated size of this relation in bytes.
It is always better to overestimate size than underestimate, because underestimation could lead to execution plans that are suboptimal (i.e. broadcasting a very large table).
Returns the list of Filters that this datasource may not be able to handle.