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Posted to dev@pig.apache.org by "Daniel Dai (JIRA)" <ji...@apache.org> on 2010/07/15 22:21:51 UTC
[jira] Commented: (PIG-1492) DefaultTuple and DefaultMemory
understimate their memory footprint
[ https://issues.apache.org/jira/browse/PIG-1492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12888905#action_12888905 ]
Daniel Dai commented on PIG-1492:
---------------------------------
Talked with Tejas, he get more observations than listed above. So I believe the formula should be good. +1 for commit once hudson pass.
> DefaultTuple and DefaultMemory understimate their memory footprint
> ------------------------------------------------------------------
>
> Key: PIG-1492
> URL: https://issues.apache.org/jira/browse/PIG-1492
> Project: Pig
> Issue Type: Bug
> Affects Versions: 0.8.0
> Reporter: Thejas M Nair
> Assignee: Thejas M Nair
> Fix For: 0.8.0
>
> Attachments: PIG-1492.1.patch
>
>
> There are several places where we highly underestimate the memory footprint . For example, for map datatypes, we don't account for the per entry cost for the map container data structures. The estimated size of a tuple having map with 100 integer key-value entries , as per current version of code is 3260 bytes, while what is observed is around 6775 bytes . To verify the memory footprint, i checked free memory before and after creating multiple instances of the object , using code on the lines of http://www.javaspecialists.eu/archive/Issue029.html .
> In PIG-1443 similar change was done to fix this for CHARARRAY .
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