[jira] [Created] (HIVE-23768) Metastore's update service wrongly strips partition column stats from the cache

2020-06-26 Thread Stamatis Zampetakis (Jira)
Stamatis Zampetakis created HIVE-23768:
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 Summary: Metastore's update service wrongly strips partition 
column stats from the cache
 Key: HIVE-23768
 URL: https://issues.apache.org/jira/browse/HIVE-23768
 Project: Hive
  Issue Type: Bug
Reporter: Stamatis Zampetakis
Assignee: Stamatis Zampetakis


Metastore's update service wrongly strips partition column stats from the cache 
in an attempt to update them. The issue may go unnoticed since missing stats do 
not lead to query failures. 

However, they can alter significantly the query plan affecting performance. 
Moreover, they lead to flakiness since some times the stats are present and 
sometimes are not leading to a query that has a different plan overtime. 

Normally missing elements from the cache shouldn't be a correctness problem 
since we can always fallback to the raw stats. Unfortunately, there are many 
interconnections with other parts of the code (e.g., code to obtain aggregate 
statistics) where this contract breaks.   



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[jira] [Created] (HIVE-23767) Send ValidWriteIDList in request for all the new HMS get_* APIs that are in request/response form

2020-06-26 Thread Kishen Das (Jira)
Kishen Das created HIVE-23767:
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 Summary: Send ValidWriteIDList in request for all the new HMS 
get_* APIs that are in request/response form
 Key: HIVE-23767
 URL: https://issues.apache.org/jira/browse/HIVE-23767
 Project: Hive
  Issue Type: Sub-task
Reporter: Kishen Das


We recently introduced new set of HMS APIs that take ValidWriteIDList in the 
request, as part of HIVE-22017.
We should switch to these new APIs, wherever required and start sending 
ValidWriteIDList in request for all the new HMS get_* APIs that are in 
request/response form.



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[jira] [Created] (HIVE-23766) Send ValidWriteIDList in request for all the new HMS get_* APIs that are in request/response form

2020-06-26 Thread Kishen Das (Jira)
Kishen Das created HIVE-23766:
-

 Summary: Send ValidWriteIDList in request for all the new HMS 
get_* APIs that are in request/response form
 Key: HIVE-23766
 URL: https://issues.apache.org/jira/browse/HIVE-23766
 Project: Hive
  Issue Type: Task
  Components: HiveServer2
Reporter: Kishen Das


We recently introduced new set of HMS APIs that take ValidWriteIDList in the 
request, as part of HIVE-22017.

We should switch to these new APIs, wherever required and start sending 
ValidWriteIDList in request for all the new HMS get_* APIs that are in 
request/response form.



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?????? ??Why the NULL will be filterd in HQL??

2020-06-26 Thread ????????
Thanks for help!


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??:"Stamatis 

Re: 【Why the NULL will be filterd in HQL】

2020-06-26 Thread Stamatis Zampetakis
Hello,

I think it would be easier to understand the problem if you have a query at
hand:

SELECT id FROM author WHERE fname != 'Victor'

0 | Victor
1 | null
2 | Alex

The query should return 2 in every standard compliant SQL database.

Victor != Victor evaluates to FALSE
null != Victor evaluates to UNKNOWN
Alex != Victor evaluates to TRUE

The WHERE clause removes tuples for which the condition evaluates to FALSE
or UNKNOWN and this is the normal behavior.

Best,
Stamatis


On Fri, Jun 26, 2020 at 2:36 AM 忝忝向仧 <153488...@qq.com> wrote:

> Hi,all:
>
>
> I want to know why the hive needs to filter the NULL when use '<' or
> '!=' in HQL?
> Normally,in Oracle or other Databases the NULL will not be filtered when
> using '<' or '!='.
> This could be a JIRA?
> Thanks!