[jira] [Updated] (PIG-4002) Disable combiner when map-side aggregation is used

["Rohini Palaniswamy (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PIG-4002?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Rohini Palaniswamy updated PIG-4002:
------------------------------------
    Fix Version/s:     (was: 0.16.0)
                   0.17.0

> Disable combiner when map-side aggregation is used
> --------------------------------------------------
>
>                 Key: PIG-4002
>                 URL: https://issues.apache.org/jira/browse/PIG-4002
>             Project: Pig
>          Issue Type: Improvement
>    Affects Versions: 0.13.0
>            Reporter: Travis Woodruff
>            Assignee: Travis Woodruff
>            Priority: Minor
>             Fix For: 0.17.0
>
>         Attachments: PIG-4002-1.patch
>
>
> This may be controversial, so I'd like others' opinions on this.
> It is not currently possible to disable the combiner and use map-side aggregation at the same time. This is a problematic since map-side aggregation effectively combines in the mapper, so running the combiner adds expensive combiner execution (combiner requires deserialization & reserialization) for little to no value.
> PIG-2829 had a patch to disable the combiner when map-side aggregation is used (along with some other changes). This was never integrated because the map-side aggregation code was redone while this was in progress.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)