[jira] Updated: (HIVE-219) Map-side aggregates output one row per reducer when not grouping

["Joydeep Sen Sarma (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-219?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Joydeep Sen Sarma updated HIVE-219:
-----------------------------------

    Priority: Blocker  (was: Critical)

this is absolutely broken.

i am trying count(1) with hive.map.aggr = true - and there is no map side aggregation happening (even though the explain has a map-side group by operator):

      Alias -> Map Operator Tree:
        mm_users_goodip_count
            Select Operator
              Group By Operator
                aggregations:
                      expr: count(1)
                mode: hash
                Reduce Output Operator
                  sort order:
                  Map-reduce partition columns:
                        expr: rand()
                        type: double
                  tag: -1
                  value expressions:
                        expr: 0
                        type: bigint

it seems that the groupbyDesc doe not have a 'keys' field specified (in other map side aggregates - i can see the keys specified). 

At any rate - the mapper emits one output row for each input row in this case. This is completely broken ..

> Map-side aggregates output one row per reducer when not grouping
> ----------------------------------------------------------------
>
>                 Key: HIVE-219
>                 URL: https://issues.apache.org/jira/browse/HIVE-219
>             Project: Hadoop Hive
>          Issue Type: Bug
>          Components: Query Processor
>            Reporter: David Phillips
>            Priority: Blocker
>
> Example: SELECT count(1) FROM table;

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