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From "Gunther Hagleitner (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-6613) Control when spcific Inputs / Outputs are started
Date Wed, 12 Mar 2014 22:57:43 GMT

    [ https://issues.apache.org/jira/browse/HIVE-6613?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13932593#comment-13932593
] 

Gunther Hagleitner commented on HIVE-6613:
------------------------------------------

Looks good. Cool to see this - should really help with memory in reducers.

Couple comments:

- Can you avoid creating a conf in TezCacheAccess? Maybe just pass it in get().
- Have you considered adding the input to the cache key instead of using a Set? That way you
can also remove the lock (I'm assuming the ObjectRegistry handles that).
- You can drop the getLocalWork check in the tez hashtable loader. Tez doesn't have local
work.
- The javadoc of the init function needs to be updated with your changes.

> Control when spcific Inputs / Outputs are started
> -------------------------------------------------
>
>                 Key: HIVE-6613
>                 URL: https://issues.apache.org/jira/browse/HIVE-6613
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Siddharth Seth
>            Assignee: Siddharth Seth
>         Attachments: TEZ-6613.1.txt
>
>
> When running with Tez - a couple of enhancement are possible
> 1) Avoid re-fetching data in case of MapJoins - since the data is likely to be cached
after the first run (container re-use for the same query)
> 2) Start Outputs only after required Inputs are ready - specifically useful in case of
Reduce - where shuffle requires a large memory, and the Output (if it's a sorted output) also
requires a fair amount of memory.



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