andrei-ionescu edited a comment on issue #1404:
URL: 
https://github.com/apache/arrow-datafusion/issues/1404#issuecomment-993912895


   I have some more question on how the hash partitioning works right now in 
DataFusion.
   
   Given 3 unique values (`val1`, `val2`, `val3`) for the `my_col` column by 
which I want to repartition my data, distributed like this: 500 rows contain 
`val1`, 5 rows contain `val2` 10K rows contain `val3`.
   
   
   What will be the result of partitioning with `Partitioning::Hash(my_col, 3)`?
   
   Will it repartition in 3 partition, partition 1 containing 500 rows all 
containing only `val1`, partition 2 with 5 rows only `val2` and partition 3 
with 10K rows containing only `val3`?
   
   -- or --
   
   Will it repartition in 3 partitions all having similar sizes, approx 3500 
each (`10K + 500 + 5 / 3`)? In this case what will each partition contain? Is 
it like: partition 1 with 3500 rows all containing `val3`, partition 2 with 
3500 rows all with `val3` and partition 3 with 500 + 5 + 3000 rows containing 
`val1` + `val2` + `val3`?
   


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