StateStoreRDD¶
StateStoreRDD
is a BaseStateStoreRDD.
Creating Instance¶
StateStoreRDD
takes the following to be created:
- Data RDD (
RDD[T]
to update the aggregates in a state store) - Store update function (
(StateStore, Iterator[T]) => Iterator[U]
whereT
is the type of rows in the data RDD) - Checkpoint directory
- Run ID of the streaming query
- Operator ID
- Store Version
- Key Schema
- Value Schema
- numColsPrefixKey
-
SessionState
- StateStoreCoordinatorRef
- Extra Options
StateStoreRDD
is created when:
StateStoreOps
is requested to mapPartitionsWithStateStore
numColsPrefixKey¶
StateStoreRDD
is given numColsPrefixKey
when created (that is passed in directly from StateStoreOps.mapPartitionsWithStateStore).
numColsPrefixKey
is used to look up a StateStore while computing a partition.