Re: Review Request 54284: StatsOptimizer should return no rows on empty table with group by

[pengcheng xiong]

> On Dec. 2, 2016, 9:10 p.m., Ashutosh Chauhan wrote:
> > ql/src/java/org/apache/hadoop/hive/ql/optimizer/StatsOptimizer.java, line 
> > 182
> > 
> >
> > Is there any differnce between NULL & constant? It seems you are not 
> > making use of NULL any where.

Yes, I have make use of NULL. Please See
{code}
if (getGbyKeyType(pgbyOp) == GbyKeyType.OTHER) {
  return null;
}
// we already check if rowCnt is null and rowCnt==0 means table is
// empty.
else if (getGbyKeyType(pgbyOp) == GbyKeyType.CONSTANT && rowCnt == 0) {
  return null;
}
{code}
That means, only if it is groupby constant and rowCnt=0, we skip the 
StatsOptimizer.
If it is NULL, which should be the 3rd condition (if, else if, else), we 
continue.


- pengcheng


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On Dec. 2, 2016, 1:23 a.m., pengcheng xiong wrote:
> 
> ---
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/54284/
> ---
> 
> (Updated Dec. 2, 2016, 1:23 a.m.)
> 
> 
> Review request for hive and Ashutosh Chauhan.
> 
> 
> Repository: hive-git
> 
> 
> Description
> ---
> 
> HIVE-13452
> 
> 
> Diffs
> -
> 
>   ql/src/java/org/apache/hadoop/hive/ql/optimizer/StatsOptimizer.java 17510e9 
>   ql/src/test/queries/clientpositive/constGby.q PRE-CREATION 
>   ql/src/test/results/clientpositive/constGby.q.out PRE-CREATION 
> 
> Diff: https://reviews.apache.org/r/54284/diff/
> 
> 
> Testing
> ---
> 
> 
> Thanks,
> 
> pengcheng xiong
> 
>

Re: Review Request 54284: StatsOptimizer should return no rows on empty table with group by

[Ashutosh Chauhan]

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ql/src/java/org/apache/hadoop/hive/ql/optimizer/StatsOptimizer.java (line 182)


Is there any differnce between NULL & constant? It seems you are not making 
use of NULL any where.


- Ashutosh Chauhan


On Dec. 2, 2016, 1:23 a.m., pengcheng xiong wrote:
> 
> ---
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/54284/
> ---
> 
> (Updated Dec. 2, 2016, 1:23 a.m.)
> 
> 
> Review request for hive and Ashutosh Chauhan.
> 
> 
> Repository: hive-git
> 
> 
> Description
> ---
> 
> HIVE-13452
> 
> 
> Diffs
> -
> 
>   ql/src/java/org/apache/hadoop/hive/ql/optimizer/StatsOptimizer.java 17510e9 
>   ql/src/test/queries/clientpositive/constGby.q PRE-CREATION 
>   ql/src/test/results/clientpositive/constGby.q.out PRE-CREATION 
> 
> Diff: https://reviews.apache.org/r/54284/diff/
> 
> 
> Testing
> ---
> 
> 
> Thanks,
> 
> pengcheng xiong
> 
>

Review Request 54284: StatsOptimizer should return no rows on empty table with group by

[pengcheng xiong]

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https://reviews.apache.org/r/54284/
---

Review request for hive and Ashutosh Chauhan.


Repository: hive-git


Description
---

HIVE-13452


Diffs
-

  ql/src/java/org/apache/hadoop/hive/ql/optimizer/StatsOptimizer.java 17510e9 
  ql/src/test/queries/clientpositive/constGby.q PRE-CREATION 
  ql/src/test/results/clientpositive/constGby.q.out PRE-CREATION 

Diff: https://reviews.apache.org/r/54284/diff/


Testing
---


Thanks,

pengcheng xiong