Dear Wiki user, You have subscribed to a wiki page or wiki category on "Pig Wiki" for change notification.
The following page has been changed by RichardDing: http://wiki.apache.org/pig/PigMultiQueryPerformanceSpecification ------------------------------------------------------------------------------ * The parallelism of the merged splitter job is the maximum of the parallelisms of all splittee jobs. * The keys from inner plans are partitioned into all the buckets via the default hash partitioner. + This scheme has advantages: + + * Simplicity. No new partition class needed. + * Performance. The parallelism of a job specified by users most likely is determined by the number of available reducers (machines), so the merged parallelism confirms to the user expectation. + To avoid the key collision of different inner plans with this scheme, the PigNullableWritable class is modified to take into account of the indexes when two keys are compared (hashed). [[Anchor(Local_Execution_engine)]]
