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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-2722) support mysql "limit,offset" clauses
Date Mon, 04 Apr 2016 23:36:25 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-2722?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15225278#comment-15225278
] 

ASF GitHub Bot commented on PHOENIX-2722:
-----------------------------------------

Github user JamesRTaylor commented on a diff in the pull request:

    https://github.com/apache/phoenix/pull/154#discussion_r58467053
  
    --- Diff: phoenix-core/src/main/java/org/apache/phoenix/compile/SubqueryRewriter.java
---
    @@ -167,7 +167,7 @@ public ParseNode visitLeave(ExistsParseNode node, List<ParseNode>
l) throws SQLE
             JoinConditionExtractor conditionExtractor = new JoinConditionExtractor(subquery,
resolver, connection, rhsTableAlias);
             ParseNode where = subquery.getWhere() == null ? null : subquery.getWhere().accept(conditionExtractor);
             if (where == subquery.getWhere()) { // non-correlated EXISTS subquery, add LIMIT
1
    -            subquery = NODE_FACTORY.select(subquery, NODE_FACTORY.limit(NODE_FACTORY.literal(1)));
    +            subquery = NODE_FACTORY.select(subquery, NODE_FACTORY.limit(NODE_FACTORY.literal(1)),
null);
    --- End diff --
    
    Always null here? Just want to confirm that this is correct.


> support mysql "limit,offset" clauses 
> -------------------------------------
>
>                 Key: PHOENIX-2722
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-2722
>             Project: Phoenix
>          Issue Type: New Feature
>            Reporter: Ankit Singhal
>            Assignee: Ankit Singhal
>            Priority: Minor
>         Attachments: PHOENIX-2722.patch, PHOENIX-2722_formatted.patch
>
>
> For serial query(query with “serial" hint or  “limit" without "order by”), we can
limit each scan(using page filter) to “limit+offset” instead of limit earlier.
> And then, for all queries, we can forward the relevant client iterators to the offset
provided and then return the result.
> syntax
> {code}
> [ LIMIT { count } ]
>     [ OFFSET start [ ROW | ROWS ] ]
>     [ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ONLY ]
> {code}
> Some new keywords(OFFSET,FETCH,ROW, ROWS,ONLY) are getting introduced so users might
need to see that they are not using them as column name or something.
> WDYT, [~jamestaylor]



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