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From "maghamravikiran (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-2088) Prevent splitting and recombining select expressions for MR integration
Date Sat, 04 Jul 2015 05:24:04 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-2088?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14613571#comment-14613571
] 

maghamravikiran commented on PHOENIX-2088:
------------------------------------------

[~jamestaylor]
   Apparently, within the pig-module, for a given LOAD statement execution, we require the
List<ColumnInfo> twice. Once , within the PhoenixInputFormat to generate the QueryPlan
for the SELECT statement and second in PhoenixPigSchemaUtil to determine the OutputSchema
for the LOAD statement. 
  By "every time" , in the case of LOAD it would be two calls to PhoenixRuntime.generateColumnInfo()
.  I don't see any performance degradation .
  Similarly, in MapReduce, it is just one time call. So we are good here.



> Prevent splitting and recombining select expressions for MR integration
> -----------------------------------------------------------------------
>
>                 Key: PHOENIX-2088
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-2088
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: James Taylor
>            Assignee: maghamravikiran
>         Attachments: PHOENIX-2088-pig.patch, PHOENIX-2088-wip-v2.patch, PHOENIX-2088-wip.patch
>
>
> We currently send in the select expressions for the MR integration with a delimiter separated
string, split based on the delimiter, and then recombine again using a comma separator. This
is problematic because the delimiter character may appear in a select expression, thus breaking
this logic. Instead, we should use a comma as the delimiter and avoid splitting and recombining
as it's not necessary in that case. Instead, the entire string can be used as-is in that case
to form the select expressions.



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