[GitHub] [arrow-datafusion] alamb opened a new issue, #3793: Improve coerce API so it doesn't need DF Schema

[GitBox <gi...@apache.org>]

alamb opened a new issue, #3793:
URL: https://github.com/apache/arrow-datafusion/issues/3793

   **Is your feature request related to a problem or challenge? Please describe what you are trying to do.**
   I am trying to use the DataFusion `Expr` struct along with the expression simplification feature -- see https://github.com/apache/arrow-datafusion/issues/3708 and https://github.com/apache/arrow-datafusion/pull/3741 for examples / description of what this means
   
   Type coercion is involved because of this chain:
   * Calling the simplify function
   * invokes the const evaluator 
   * evaluated expressions via `PhysicalExpr
   * which requires the expression types to match  (after #3468)
   
   https://github.com/apache/arrow-datafusion/pull/3758 adds an API to call coerce so that simplify can work in more cases.
   
   However, the API requires a `DFSchema`, some wrapper type over `Schema` that is non trivial to compute. The Simplify API already takes a trait [`SimplifyInfo`](https://docs.rs/datafusion/13.0.0/datafusion/logical_plan/trait.SimplifyInfo.html) to provide just the information required. It would be nice if the coercion function did too, and was called directly as part of the coercion API. 
   
   **Describe the solution you'd like**
   I would like the signature of `coerce` addd in https://github.com/apache/arrow-datafusion/pull/3758 to take a `SimplifyInfo` rather than `DFSchema`
   
   **Describe alternatives you've considered**
   A clear and concise description of any alternative solutions or features you've considered.
   
   **Additional context**
   See https://github.com/influxdata/influxdb_iox/pull/5792 for examples of when IOx uses the simplification (and thus needs to call coerce)


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Re: [I] Improve coerce API so it doesn't need DF Schema [datafusion]

["alamb (via GitHub)" <gi...@apache.org>]

alamb closed issue #3793: Improve coerce API so it doesn't need DF Schema
URL: https://github.com/apache/datafusion/issues/3793


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