phoenix-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Lars Hofhansl (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-258) Use skip scan when SELECT DISTINCT on leading row key column(s)
Date Wed, 01 Jun 2016 05:09:12 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-258?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15309272#comment-15309272
] 

Lars Hofhansl commented on PHOENIX-258:
---------------------------------------

Hmm... isOrderPreserving is calculated like this:
{{isOrderPreserving &= entry.orderPreserving != OrderPreserving.NO && prevOrderPreserving
== OrderPreserving.YES && (pos == prevPos || pos - prevSlotSpan == prevPos  || hasEqualityConstraints(prevPos+prevSlotSpan,
pos)}};
and it is also set in the track(...) method. Not sure I want to mess with that - and convince
myself that everything works exactly the same.


> Use skip scan when SELECT DISTINCT on leading row key column(s)
> ---------------------------------------------------------------
>
>                 Key: PHOENIX-258
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-258
>             Project: Phoenix
>          Issue Type: Task
>            Reporter: ryang-sfdc
>            Assignee: Lars Hofhansl
>             Fix For: 4.8.0
>
>         Attachments: 258-WIP.txt, 258-v1.txt, 258-v10.txt, 258-v11.txt, 258-v12.txt,
258-v2.txt, 258-v3.txt, 258-v4.txt, 258-v5.txt, 258-v6.txt, 258-v7.txt, 258-v8.txt, 258-v9.txt,
258.txt, DistinctFixedPrefixFilter.java, in-clause.png
>
>
> create table(a varchar(32) not null, date date not null constraint pk primary key(a,date))
> [["PLAN"],["CLIENT PARALLEL 94-WAY FULL SCAN OVER foo"],["    SERVER AGGREGATE INTO ORDERED
DISTINCT ROWS BY [a]"],["CLIENT MERGE SORT"]]             
> We should skip scan.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message