BaseRelation — Collection of Tuples with Schema¶
BaseRelation represents an external data source with data to load datasets from or write to.
BaseRelation is "created" when
DataSource is requested to resolve a relation.
BaseRelation is then transformed into a
SparkSession is requested to create a DataFrame.
Schema of the tuples of the relation
Estimated size of the relation (in bytes)
Default: spark.sql.defaultSizeInBytes configuration property
Controls type conversion (whether or not JVM objects inside Rows needs to be converted to Catalyst types, e.g.
It is recommended to leave
needConversion enabled (as is) for custom data sources (outside Spark SQL).
unhandledFilters( filters: Array[Filter]): Array[Filter]
Filter predicates that the relation does not support (handle) natively
Default: the input filters (as it is considered safe to double evaluate filters regardless whether they could be supported or not)