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From "Saikat (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (TEZ-2574) Make a better Metadata Value split choice in Pipeline sort
Date Sat, 04 Jul 2015 22:40:04 GMT

     [ https://issues.apache.org/jira/browse/TEZ-2574?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Saikat updated TEZ-2574:
------------------------
    Attachment: TEZ-2574.1.patch

Added changes as per discussion on top of 2575 patch

> Make a better Metadata Value split choice in Pipeline sort
> ----------------------------------------------------------
>
>                 Key: TEZ-2574
>                 URL: https://issues.apache.org/jira/browse/TEZ-2574
>             Project: Apache Tez
>          Issue Type: Improvement
>            Reporter: Saikat
>            Assignee: Saikat
>         Attachments: TEZ-2574.1.patch, TEZ-2574.patch
>
>
> In the current implementation of pipeline sort, when a new sort span object is created
with a hard coded value of 1M items and 16 bytes per item.
> According to the present code logic, 
>       int metasize = METASIZE*maxItems;
>       int dataSize = maxItems * perItem;
>       if(capacity < (metasize+dataSize)) {
>         // try to allocate less meta space, because we have sample data
>         metasize = METASIZE*(capacity/(perItem+METASIZE));
>       }
> if capacity is less than 32mb, the buffer will be halved into meta and value buffers,
which is not efficient.
> We need a more generic split, based on the KV pair size written to the buffer.



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