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  1. Hive
  2. HIVE-6614

Vectorized aggregates computed on map side diffe (hash mode) from values computed on reduce side (streaming mode)

    Details

    • Type: Bug
    • Status: Open
    • Priority: Critical
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
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      Description

      HIVE-6222 allows vectorized aggregates to operate on streaming mode, ie. flush after each key change and let the shuffle+reduce side to compute the final aggregate values. An error in patch .2 for HIVE-6222 shows that when the queries run in streaming mode, there are rounding diffs for some agg functions (VAR and friends). These occurred for non-decimal types, like ctinyint:

      select csmallint, VAR_POP(ctinyint) from alltypesorc where csmallint = -75 group by csmallint;
      

      This produces 107.55555555555556 vs. 107.55555555555554.

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            • Assignee:
              rusanu Remus Rusanu
              Reporter:
              rusanu Remus Rusanu
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              • Created:
                Updated: