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From "Zheng Shao (JIRA)" <>
Subject [jira] Commented: (HIVE-352) Make Hive support column based storage
Date Mon, 20 Apr 2009 21:22:47 GMT


Zheng Shao commented on HIVE-352:

I agree we should do 1 and 2, but I don't feel 3 is worth to do.
As you mentioned, 3 will have memory problems when the number of columns grows very big -
in that case, performance degradation is better than out-of-memory problem.

For 3 the eventual solution would be to fix DFSClient to use a smaller number than TCP_WINDOW_SIZE.
But if it is not easy to change DFSClient, and we continue to see this problem, we may want
to switch to other solutions (B1 etc). Anyway, if TCP_WINDOW_SIZE is 128KB, and we have 20MB
buffer (compressed size), we should be able to handle 160 columns, which is usually good enough
for most applications.

> Make Hive support column based storage
> --------------------------------------
>                 Key: HIVE-352
>                 URL:
>             Project: Hadoop Hive
>          Issue Type: New Feature
>            Reporter: He Yongqiang
>            Assignee: He Yongqiang
>         Attachments: hive-352-2009-4-15.patch, hive-352-2009-4-16.patch, hive-352-2009-4-17.patch,
hive-352-2009-4-19.patch, HIve-352-draft-2009-03-28.patch, Hive-352-draft-2009-03-30.patch
> column based storage has been proven a better storage layout for OLAP. 
> Hive does a great job on raw row oriented storage. In this issue, we will enhance hive
to support column based storage. 
> Acctually we have done some work on column based storage on top of hdfs, i think it will
need some review and refactoring to port it to Hive.
> Any thoughts?

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