[jira] [Commented] (HIVE-4963) Support in memory PTF partitions

["Lefty Leverenz (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-4963?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14207516#comment-14207516 ] 

Lefty Leverenz commented on HIVE-4963:
--------------------------------------

bq.  Could someone either document this on the Wiki or explain it to me?

The wiki doesn't have a section about PTFs yet, and the description of *hive.join.cache.size* hasn't been changed since Hive 0.5.0:  "How many rows in the joining tables (except the streaming table) should be cached in memory."

So I'm adding a TODOC12 label.  What should the wiki say?

> Support in memory PTF partitions
> --------------------------------
>
>                 Key: HIVE-4963
>                 URL: https://issues.apache.org/jira/browse/HIVE-4963
>             Project: Hive
>          Issue Type: New Feature
>          Components: PTF-Windowing
>            Reporter: Harish Butani
>            Assignee: Harish Butani
>             Fix For: 0.12.0
>
>         Attachments: HIVE-4963.D11955.1.patch, HIVE-4963.D12279.1.patch, HIVE-4963.D12279.2.patch, HIVE-4963.D12279.3.patch, PTFRowContainer.patch
>
>
> PTF partitions apply the defensive mode of assuming that partitions will not fit in memory. Because of this there is a significant deserialization overhead when accessing elements. 
> Allow the user to specify that there is enough memory to hold partitions through a 'hive.ptf.partition.fits.in.mem' option.  
> Savings depends on partition size and in case of windowing the number of UDAFs and the window ranges. For eg for the following (admittedly extreme) case the PTFOperator exec times went from 39 secs to 8 secs.
>  
> {noformat}
> select t, s, i, b, f, d,
> min(t) over(partition by 1 rows between unbounded preceding and current row), 
> min(s) over(partition by 1 rows between unbounded preceding and current row), 
> min(i) over(partition by 1 rows between unbounded preceding and current row), 
> min(b) over(partition by 1 rows between unbounded preceding and current row) 
> from over10k
> {noformat}



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