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From "Maryann Xue (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (PHOENIX-2262) Improve collation for salted table
Date Thu, 05 Nov 2015 02:16:27 GMT

     [ https://issues.apache.org/jira/browse/PHOENIX-2262?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Maryann Xue updated PHOENIX-2262:
---------------------------------
    Description: 
Salting tables have a leading SALT column so it's collation is "salted distribution" + "pk
ordering". We have to set the "forceRowKeyOrder" flag to true to guarantee PK order in a scan
but meanwhile forcing row key order could be a big performance penalty.
The idea is to use "forceRowKeyOrder" whenever the PK order is useful (e.g. to avoid sorting,
to use stream aggregate, etc.), but disable this flag when the order is not needed.

  was:Salting tables have a leading SALT column so it's collation is "salted distribution"
+ "pk ordering". For now we simply set it to empty collation. We may have to introduce an
operator for merge-sort of salted table scan result.


> Improve collation for salted table
> ----------------------------------
>
>                 Key: PHOENIX-2262
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-2262
>             Project: Phoenix
>          Issue Type: Improvement
>            Reporter: Maryann Xue
>            Assignee: Maryann Xue
>            Priority: Minor
>              Labels: calcite
>
> Salting tables have a leading SALT column so it's collation is "salted distribution"
+ "pk ordering". We have to set the "forceRowKeyOrder" flag to true to guarantee PK order
in a scan but meanwhile forcing row key order could be a big performance penalty.
> The idea is to use "forceRowKeyOrder" whenever the PK order is useful (e.g. to avoid
sorting, to use stream aggregate, etc.), but disable this flag when the order is not needed.



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