SparkStrategies — Container of Execution Planning Strategies¶

SparkStrategies is an abstract Catalyst query planner that merely serves as a "container" (or a namespace) of the concrete execution planning strategies (for SparkPlanner):

• Aggregation
• BasicOperators
• FlatMapGroupsWithStateStrategy
• InMemoryScans
• JoinSelection
• SpecialLimits
• StatefulAggregationStrategy
• StreamingDeduplicationStrategy
• StreamingRelationStrategy

[[singleRowRdd]] SparkStrategies has a single lazily-instantiated singleRowRdd value that is an RDD of InternalRows that BasicOperators execution planning strategy uses when resolving OneRowRelation (to RDDScanExec leaf physical operator).

NOTE: OneRowRelation logical operator represents SQL's SELECT clause without FROM clause or EXPLAIN DESCRIBE TABLE.