[jira] [Updated] (PHOENIX-2194) order by should not require all PK fields with = constraint

["James Taylor (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PHOENIX-2194?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

James Taylor updated PHOENIX-2194:
----------------------------------
    Attachment: PHOENIX-2194.patch

WIP patch to improve when ORDER BY is optimized out based on equality constraints in WHERE clause.

> order by should not require all PK fields with = constraint
> -----------------------------------------------------------
>
>                 Key: PHOENIX-2194
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-2194
>             Project: Phoenix
>          Issue Type: Bug
>    Affects Versions: 4.5.0
>         Environment: linux
>            Reporter: Gary Horen
>              Labels: AtMention, SFDC
>         Attachments: PHOENIX-2194.patch
>
>
> Here is a table:
> CREATE TABLE IF NOT EXISTS FEEDS.STUFF
> (
>     STUFF CHAR(15) NOT NULL,
>     NONSENSE CHAR(15) NOT NULL
>     CONSTRAINT PK PRIMARY KEY
>     (
>         STUFF,
>         NONSENSE
>     
>     )
> ) VERSIONS=1,MULTI_TENANT=TRUE,REPLICATION_SCOPE=1
> Here is a query:
> explain SELECT * FROM feeds.stuff
> where stuff = ' '
> and nonsense > ' '
> order by nonsense
> Here is the plan:
> CLIENT 1-CHUNK PARALLEL 1-WAY RANGE SCAN  
>     SERVER FILTER BY FIRST KEY ONLY       
>     SERVER TOP 100 ROWS SORTED BY [NONSE  
> CLIENT MERGE SORT   
> If I change to ORDER BY STUFF, NONSENSE I get:
> CLIENT 1-CHUNK SERIAL 1-WAY RANGE SCAN O  
>     SERVER FILTER BY FIRST KEY ONLY AND   
>     SERVER 100 ROW LIMIT                  
> CLIENT 100 ROW LIMIT                      
> Since the leading constraint is =,  ORDER BY will be unaffected by it, so ORDER BY should not need the leading constraint; it should only require the columns whose values would vary (which, since they are ordered by the key, should (and do) result in the client side sort being optimized out.) Having to include the leading = constraints in the ORDER BY clause is very counter-intuitive.



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