andygrove opened a new issue, #824:
URL: https://github.com/apache/datafusion-comet/issues/824
### What is the problem the feature request solves?
I am benchmarking with this query (based on TPC-DS q39):
```sql
select w_warehouse_name,w_warehouse_sk,i_item_sk,d_moy
,stddev_samp(inv_quantity_on_hand) stdev
from inventory
,item
,warehouse
,date_dim
where inv_item_sk = i_item_sk
and inv_warehouse_sk = w_warehouse_sk
and inv_date_sk = d_date_sk
and d_year =2001
group by w_warehouse_name,w_warehouse_sk,i_item_sk,d_moy;
```
Results:
```
AMD Ryzen 9 7950X3D 16-Core Processor
TPCDS Micro Benchmarks: Best Time(ms) Avg Time(ms)
Stdev(ms) Rate(M/s) Per Row(ns) Relative
stddev 3295 3370
105 40.4 24.7 1.0X
stddev: Comet (Scan) 3343 3461
167 39.9 25.1 1.0X
stddev: Comet (Scan, Exec) 7621 7657
50 17.5 57.2 0.4X
```
If I change the query to use `avg` instead of `stddev` then I get much
better results (ignore the benchmark name):
```
AMD Ryzen 9 7950X3D 16-Core Processor
TPCDS Micro Benchmarks: Best Time(ms) Avg Time(ms)
Stdev(ms) Rate(M/s) Per Row(ns) Relative
stddev 3187 3276
125 41.8 23.9 1.0X
stddev: Comet (Scan) 3128 3163
48 42.6 23.5 1.0X
stddev: Comet (Scan, Exec) 2209 2241
44 60.3 16.6 1.4X
```
### Describe the potential solution
_No response_
### Additional context
_No response_
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