gokselk opened a new issue, #13839:
URL: https://github.com/apache/datafusion/issues/13839
### Is your feature request related to a problem or challenge?
Currently, DataFusion's ordering equivalence only works with
single-parameter monotonic functions. We need to support functions with
multiple parameters to enable more optimization opportunities.
Example:
- Table ordered by `[c ASC, a ASC, b ASC]` with equality `c = concat(a, b)`
- Since `concat()` preserves lexicographical order, then `[a ASC, b ASC]`
should be valid ordering
### Describe the solution you'd like
Add support for N-ary monotonic functions by:
1. Add `preserves_lex_ordering` property to ExprProperties
2. Implement for `concat()` function
3. Update ordering equivalence logic to handle multiple parameters
### Describe alternatives you've considered
_No response_
### Additional context
This will improve query optimization by allowing more valid orderings to be
discovered.
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