示例:表XXXX是由column1和column2划分的。
reading table XXXX by where clause Column1 and column2
option 1: select xxxx where column1 ="" and column2 =""
option 2: select xxxx where column2 ="" and column1 =""
does option 1 and option 2 has different read performance because of filter order and table partitionBy column1 and column2?
i have checked DAG for both case which is having partitionFilter in filescan.
question is
option1 : where(column1 ="" and column2 ="")
option 2: where(column2 ="" and column1 ="" )
does it have differenet read performance beacuse of table patition by column1, column2?发布于 2022-09-07 09:56:57
我想说,这应该没有什么区别,因为最终映射(即添加了以获取第一个分区,然后是第二个分区)的总处理时间将以相同的方式发生。基本上..。
t(column1) + t(column2) = t(column2) + t(column1)
但这是一个棘手的问题,应该用不同的基数和格式对每一列进行测试。
https://stackoverflow.com/questions/67502526
复制相似问题