[ https://issues.apache.org/jira/browse/HIVE-26978 ]


    Zoltan Haindrich deleted comment on HIVE-26978:
    -----------------------------------------

was (Author: kgyrtkirk):
have you restarted the HS2?
the runtime stats are cached there; the metastore only stores them

> Stale "Runtime stats" causes poor query planning
> ------------------------------------------------
>
>                 Key: HIVE-26978
>                 URL: https://issues.apache.org/jira/browse/HIVE-26978
>             Project: Hive
>          Issue Type: Improvement
>          Components: HiveServer2
>            Reporter: Rajesh Balamohan
>            Priority: Major
>              Labels: performance
>         Attachments: Screenshot 2023-01-24 at 10.23.16 AM.png
>
>
> * Runtime stats can be stored in hiveserver or in metastore via 
> "hive.query.reexecution.stats.persist.scope".
>  * Though the table is dropped and recreated, it ends up showing old stats 
> via "RUNTIME" stats. Here is an example (note that the table is empty, but 
> gets datasize and numRows from RUNTIME stats)
>  * This causes suboptimal plan for "MERGE INTO" queries by creating 
> CUSTOM_EDGE instead of broadcast edge.
> !Screenshot 2023-01-24 at 10.23.16 AM.png|width=2053,height=753!
>  
>  



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