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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (PHOENIX-4602) OrExpression should can also push non-leading pk columns to scan
Date Tue, 13 Feb 2018 19:33:00 GMT

     [ https://issues.apache.org/jira/browse/PHOENIX-4602?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

James Taylor updated PHOENIX-4602:
----------------------------------
    Fix Version/s: 4.14.0

> OrExpression should can also push non-leading pk columns to scan
> ----------------------------------------------------------------
>
>                 Key: PHOENIX-4602
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-4602
>             Project: Phoenix
>          Issue Type: Improvement
>    Affects Versions: 4.13.0
>            Reporter: chenglei
>            Priority: Major
>             Fix For: 4.14.0
>
>         Attachments: PHOENIX-4602_v1.patch
>
>
> Given following table:
> {code}
>     CREATE TABLE test_table (
>      PK1 INTEGER NOT NULL,
>      PK2 INTEGER NOT NULL,
>      PK3 INTEGER NOT NULL,
>      DATA INTEGER, 
>      CONSTRAINT TEST_PK PRIMARY KEY (PK1,PK2,PK3))
> {code}
> and a sql:
> {code}
>   select * from test_table t where (t.pk1 >=2 and t.pk1<5) and ((t.pk2 >= 4
and t.pk2 <6) or (t.pk2 >= 8 and t.pk2 <9))
> {code}
> Obviously, it is a typical case for the sql to use SkipScanFilter,however, the sql actually
does not use Skip Scan, it use Range Scan and just push the leading pk column expression {{(t.pk1
>=2 and t.pk1<5)}} to scan,the explain sql is :
>  {code:sql}
>    CLIENT PARALLEL 1-WAY RANGE SCAN OVER TEST_TABLE [2] - [5]
>        SERVER FILTER BY ((PK2 >= 4 AND PK2 < 6) OR (PK2 >= 8 AND PK2 <
9))
> {code}
>  I think the problem is affected by the {{WhereOptimizer.KeyExpressionVisitor.orKeySlots}}
method, in the following line 763, because the pk2 column is not the leading pk column,so
this method return null, causing the expression 
> {{((t.pk2 >= 4 and t.pk2 <6) or (t.pk2 >= 8 and t.pk2 <9))}} is not  pushed
to scan:
> {code:java}
> 757    boolean hasFirstSlot = true;
> 758    boolean prevIsNull = false;
> 759    // TODO: Do the same optimization that we do for IN if the childSlots specify
a fully qualified row key
> 760   for (KeySlot slot : childSlot) {
> 761      if (hasFirstSlot) {
> 762           // if the first slot is null, return null immediately
> 763           if (slot == null) {
> 764                return null;
> 765            }
> 766           // mark that we've handled the first slot
> 767           hasFirstSlot = false;
> 768      }
> {code}
> For above {{WhereOptimizer.KeyExpressionVisitor.orKeySlots}} method, it seems that it
is not necessary to make sure the PK Column in OrExpression is leading PK Column,just guarantee
there is only one PK Column in OrExpression is enough.  
>  



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