Defined in File BatchWindowFunctionProcessing.h
public ral::cache::kernel(Class kernel)
OverlapGeneratorKernel: public ral::cache::kernel¶
The OverlapGeneratorKernel is only used for window functions that have no partition by clause and that also have bounded window frames. The OverlapGeneratorKernel assumes that it will be following by OverlapAccumulatorKernel and has three output caches:
Its purpose is to take its input batches and create preceding and/or following overlaps depending on the preceding and following clauses of the window frames. It operates on each batch independently and does not communicate with other nodes. If it cannot create a complte overlap (the overlap size is bigger than the batch), it will set the overlap’s status to INCOMPLETE, which is captured by the CacheData metadata for the overlap.
inline virtual std::string
Executes the batch processing. Loads the data from their input port, and after processing it, the results are stored in their output port.
kstatus ‘stop’ to halt processing, or ‘proceed’ to continue processing.