Details
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New Feature
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Status: Closed
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Major
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Resolution: Fixed
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None
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None
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Reviewed
Description
Currently if hive.merge.mapfiles/mapredfiles=true, a new mapreduce job is create to read the input files and output to one reducer for merging. This MR job is created at compile time and one MR job for one partition. In the case of dynamic partition case, multiple partitions could be created at execution time and generating merging MR job at compile time is impossible.
We should generalize the merge framework to allow multiple partitions and most of the time a map-only job should be sufficient if we use CombineHiveInputFormat.