Function analyze_query_plan_schema 

pub fn analyze_query_plan_schema(
    routines: &dyn RoutineResolution,
    plan: &QueryPlan,
    params: &[SQLParam],
    ctes: &BindingContext<'_>,
    outer: Option<&RowSchema>,
) -> Result<RowSchema, SQLError>

Analyze every catalog and scalar reference and derive the exact output row type without executing the query.