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The following page has been changed by GuntherHagleitner: http://wiki.apache.org/pig/PigMultiQueryPerformanceSpecification ------------------------------------------------------------------------------ * Allows for param substitution in scripts. [[Anchor(Turning_off_multi_query)]] - === Turning off multi query === + === Turning off the multi-query optimization === By default the multi-query optimization is enabled and scripts execution will be handled accordingly. If it is desired to turn off the optimization and revert to "execute-on-store" behavior, the "-M" or "-no_multiquery" switches can be used. @@ -398, +398 @@ attachment:mapreduce.png + If a split happens in a reduce plan, splittees have to be map-only jobs to be merged into the splitter. + If there are map-reduce splittees the reduce will result in a tmp store and the splittees are run in separate + jobs. + + [[Anchor(Multi_input_splittee)]] + ==== Multi-input splittees ==== + + Splittees that have multiple inputs (such as produced by cogroup or join) are not merged into the splitter. In + this case the splitter will write the split input to a temporary file and the splittee will be started in a + different job. + [[Anchor(Store_load_bridge)]] === Store-load sequences ===
