kmitchener commented on PR #3242:
URL:
https://github.com/apache/arrow-datafusion/pull/3242#issuecomment-1224969592
Given the above sql, it results in this plan. Isn't this 1 too many
projections?
```
create view v as select 1 as a, 2 as b, 3 as c;
explain analyze select * from (select b from v);
+-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| plan_type | plan
|
+-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Plan with Metrics | CoalescePartitionsExec, metrics=[output_rows=1,
elapsed_compute=72.1µs, spill_count=0, spilled_bytes=0, mem_used=0]
|
| | ProjectionExec: expr=[b@0 as b],
metrics=[output_rows=1, elapsed_compute=3.311µs, spill_count=0,
spilled_bytes=0, mem_used=0] |
| | ProjectionExec: expr=[b@0 as b],
metrics=[output_rows=1, elapsed_compute=5.511µs, spill_count=0,
spilled_bytes=0, mem_used=0] |
| | ProjectionExec: expr=[2 as b],
metrics=[output_rows=1, elapsed_compute=53.011µs, spill_count=0,
spilled_bytes=0, mem_used=0] |
| | RepartitionExec:
partitioning=RoundRobinBatch(12), metrics=[repart_time{inputPartition=0}=1ns,
fetch_time{inputPartition=0}=27µs, send_time{inputPartition=0}=7.6µs] |
| | EmptyExec: produce_one_row=true, metrics=[]
|
| |
|
+-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
```
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