[GitHub] [arrow] Dandandan edited a comment on pull request #8961: ARROW-10885: [Rust][DataFusion] Optimize hash join build vs probe order based on number of rows

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Dandandan edited a comment on pull request #8961:
URL: https://github.com/apache/arrow/pull/8961#issuecomment-748437288


   I checked merging the other PR https://github.com/apache/arrow/pull/8965 
which improves the join implementation.
   
   Besides being much fastest regardless of this PR, reordering gives a further 
~15% reduction in time when reordering the following query (6001214 vs 1499999 
rows)
   
   ```
   select
                   l_shipmode,
                   sum(case
                       when o_orderpriority = '1-URGENT'
                           or o_orderpriority = '2-HIGH'
                           then 1
                       else 0
                   end) as high_line_count,
                   sum(case
                       when o_orderpriority <> '1-URGENT'
                           and o_orderpriority <> '2-HIGH'
                           then 1
                       else 0
                   end) as low_line_count
               from
                   lineitem
               join
                   orders
               on
                   l_orderkey = o_orderkey
               group by
                   l_shipmode
               order by
                   l_shipmode;"
   ```


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