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too many tasks when I read a distributed partitioned table using partition key filter #225

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ScalaFirst opened this issue Mar 10, 2023 · 1 comment
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enhancement New feature or request

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@ScalaFirst
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ScalaFirst commented Mar 10, 2023

dependency:

com.github.housepower
clickhouse-spark-runtime-3.2_2.12
0.5.0

my sql is :
select * from xxx where dt (this is my partition key) = '2023-03-09' ,
the database has not value , so I think this sql will complete quickly but not.
I found the filter message is :

Pushing operators to label_platform.ch_label_crowd_export
Pushed Filters: EqualTo(dt,2023-03-09)
Post-Scan Filters:

and total tasks count is : 1124
I think best performance tasks total should be 1 task because I have no data in dt = '2023-03-09'

@pan3793
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pan3793 commented Mar 10, 2023

that's a good point, we can collect more metrics during the planning phase, and eliminate task assignments for those partitions which do not contain any data.

@mzitnik mzitnik added the enhancement New feature or request label Jun 30, 2024
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