jiangzhx commented on issue #1246:
URL:
https://github.com/apache/arrow-datafusion/issues/1246#issuecomment-961646148
> If I recall correctly, datafusion doesn't do fine optimization about
`group by` and `aggregate functions` at present. It's worth adding it to our
RoadMap and doing it in the future.
i try to dig code in trino and doris; there are all have streaming aggregate
node; but i can't understand how they working.
`aggregate functions` was working fine; with sum(LO_EXTENDEDPRICE) or
without; the performence has no big difference,there are also have 5~10 times
slow;
low cardinality:
select 1 FROM lineorder_flat group by LO_ORDERPRIORITY;
5 rows in set. Query took 0.236 seconds.
high cardinality:
select 1 FROM lineorder_flat group by S_ADDRESS;
20000 rows in set. Query took 1.429 seconds.
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