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From aertoria <...@git.apache.org>
Subject [GitHub] phoenix pull request #262: PHOENIX 153 implement TABLESAMPLE clause
Date Fri, 16 Jun 2017 20:25:11 GMT
GitHub user aertoria opened a pull request:

    https://github.com/apache/phoenix/pull/262

    PHOENIX 153 implement TABLESAMPLE clause

    table sampling on each Table basis (at the 'FROM' part of the query). Sample size decided
by the input sampling rate applies on Primary Key's frequency.
    
    Syntax: 
    `select name from person SAMPLE(0.10) where name='ethan'`
    
    
    ++
    ++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;
    
    ===AGGREGATION===
    select count(*) from PERSON TABLESAMPLE 0.5 LIMIT 2
    select count(*) from (select NAME from PERSON limit 20)
    
    ===SUB QUERY===
    select * from (select /*+NO_INDEX*/ * from PERSON tablesample 0.1 where Name > 'tina10')
where ADDRESS = 'CA'
    
    ===JOINS===
    select * from PERSON1, PERSON2 tablesample 0.7 where PERSON1.Name = PERSON2.NAME
    
    ===QUERY being OPTMIZED===
    select * from PERSON tablesample 0.8 (goes to IDX_ADDRESS_PERSON index table, table sample
carry on)
    
    ===INSERT SELECT====
    upsert into personbig(ID, ADDRESS) select id, address from personbig tablesample 0.01;


You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/aertoria/phoenix master

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/phoenix/pull/262.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #262
    
----
commit c872defc5cc3ef7f4d264b207d831ceb3a71ef2d
Author: aertoria <castives@gmail.com>
Date:   2017-06-16T20:21:34Z

    PHOENIX 153 implement TABLESAMPLE clause

----


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