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Posted to dev@phoenix.apache.org by "Maryann Xue (JIRA)" <ji...@apache.org> on 2015/11/05 03:16:27 UTC

[jira] [Updated] (PHOENIX-2262) Improve collation for salted table

     [ 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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