Method rewrite_plan

datafusion/optimizer/src/analyzer/function_rewrite.rs:44–79

Rewrite a single plan, and all its expressions using the provided rewriters

(
        &self,
        plan: LogicalPlan,
        options: &ConfigOptions,
    )

    /// Rewrite a single plan, and all its expressions using the provided rewriters
    fn rewrite_plan(
        &self,
        plan: LogicalPlan,
        options: &ConfigOptions,
    ) -> Result<Transformed<LogicalPlan>> {
        // get schema representing all available input fields. This is used for data type
        // resolution only, so order does not matter here
        let mut schema = merge_schema(&plan.inputs());

        if let LogicalPlan::TableScan(ts) = &plan {
            let source_schema = DFSchema::try_from_qualified_schema(
                ts.table_name.clone(),
                &ts.source.schema(),
            )?;
            schema.merge(&source_schema);
        }

        let name_preserver = NamePreserver::new(&plan);

        plan.map_expressions(|expr| {
            let original_name = name_preserver.save(&expr);

            // recursively transform the expression, applying the rewrites at each step
            let transformed_expr = expr.transform_up(|expr| {
                let mut result = Transformed::no(expr);
                for rewriter in self.function_rewrites.iter() {
                    result = result.transform_data(|expr| {
                        rewriter.rewrite(expr, &schema, options)
                    })?;
                }
                Ok(result)
            })?;

            Ok(transformed_expr.update_data(|expr| original_name.restore(expr)))
        })
    }
}

impl AnalyzerRule for ApplyFunctionRewrites {