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Optimizer adds redundant projections on casts with confusing alias #3786
Description
Describe the bug
#3764 fixed one regression but introduced another.
I do not understand why this additional projection is being added.
Before
Inner Join: store_sales.ss_sold_date_sk = date_dim.d_date_sk
After
Projection: CAST(date_dim.d_moy AS Int64) AS CAST(date_dim.d_moy AS Int64)date_dim.d_moy, store_sales.ss_customer_sk, date_dim.d_year
Inner Join: store_sales.ss_sold_date_sk = date_dim.d_date_sk
To Reproduce
No repro available yet
Expected behavior
Additional context
Activity
[-]Optimizer reduntant projections on casts with confusing alias[/-][+]Optimizer adds reduntant projections on casts with confusing alias[/+][-]Optimizer adds reduntant projections on casts with confusing alias[/-][+]Optimizer adds redundant projections on casts with confusing alias[/+]alamb commentedon Oct 11, 2022
Note I tried to explain in #3794 why aliases are needed for optimizer rewrite passes in general.
This may also be related to #3770
alamb commentedon Oct 11, 2022
Using
EXPLAIN VERBOSEon the plan should reveal which optimizer pass is making this change. If I had to guess, I would guess CommonSubexprEliminateliukun4515 commentedon Oct 12, 2022
Maybe related to this issue #3635 which will produce redundant projection after run the optimizer
andygrove commentedon Oct 17, 2022
Another example:
The alias name should just be:
and not
andygrove commentedon Oct 25, 2022
Another example in #3884 (comment)
andygrove commentedon Nov 1, 2022
I confirmed that this does happen in
common_sub_expression_eliminateandygrove commentedon Nov 1, 2022
Fixing this will involve a significant refactor/rewrite of portions of
common_sub_expression_eliminatejackwener commentedon Dec 11, 2022
related with #4575