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https://issues.apache.org/jira/browse/PHOENIX-153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16044823#comment-16044823
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Ethan Wang commented on PHOENIX-153:
------------------------------------
Spec of this patch. Feedback plz.
++
++Belows are SUPPORTED
++
===BASE CASE====
select * from Person;
select * from PERSON TABLESAMPLE 0.45;
===WHERE CLAUSE====
select * from PERSON where ADDRESS = 'CA' OR name>'tina3';
select * from PERSON TABLESAMPLE 0.49 where ADDRESS = 'CA' OR name>'tina3';
select * from PERSON TABLESAMPLE 0.49 where ADDRESS = 'CA' OR name>'tina3'
LIMIT 1;
===Wired Table===
select * from LOCAL_ADDRESS TABLESAMPLE 0.79;
select * from SYSTEM.STATS TABLESAMPLE 0.41;
===CORNER CASE===
select * from PERSON TABLESAMPLE 0;
select * from PERSON TABLESAMPLE 1.45;
select * from PERSON TABLESAMPLE kko;
++
++belows are NOT SUPPORTED
++
===Subquery and outter join not supporting===
select * from (select * from PERSON where ADDRESS = 'CA') TABLESAMPE 0.2 where
Name > 'tina10'
===AGGREGATION===
select count(*) from PERSON TABLESAMPLE 0.5 LIMIT 2
> Implement TABLESAMPLE clause
> ----------------------------
>
> Key: PHOENIX-153
> URL: https://issues.apache.org/jira/browse/PHOENIX-153
> Project: Phoenix
> Issue Type: Task
> Reporter: James Taylor
> Assignee: Ethan Wang
> Labels: enhancement
>
> Support the standard SQL TABLESAMPLE clause by implementing a filter that
> uses a skip next hint based on the region boundaries of the table to only
> return n rows per region.
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