Interface QueryParallelizer

All Superinterfaces:
ParallelizationParameters
All Known Implementing Classes:
DefaultQueryParallelizer, QueueQueryParallelizer, SimpleParallelizer, SplittingParallelizer

public interface QueryParallelizer extends ParallelizationParameters
Parallelizes the query plan. Once the optimizer finishes its job by producing a optimized plan, it is the job of this parallelizer to generate a parallel plan out of the optimized physical plan. It does so by using the optimizers estimates for row count etc. There are two kinds of parallelizers as explained below. Currently the difference in both of these parallelizers is only in the memory assignment for the physical operators.

a) Default Parallelizer: It optimistically assumes that the whole cluster is running only the current query and based on heuristics assigns the optimal memory to the buffered operators.

b) Queue Parallelizer: This parallelizer computes the memory that can be allocated at best based on the current cluster state(as to how much memory is available) and also the configuration of the queue that it can run on.

  • Method Details