Skip casting to binary when inner expr is value #60
+46
−19
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Rationale for this change
Datafusion enforces an eager cast of value to binary value in the logical plan where a comparison with binary value is presented. For example, in the following plan
Filter: value = CAST(Utf8("binary_value") AS BinaryHowever, when using unparser to convert the plan back to sql, where the sql will be sent to various query engine (e.g. DuckDB). the cast is not needed for the value, in the example above the value "binary_value", since the raw value can be directly used in SQL engines without casting to an engine specific dictionary type. Therefore, the plan can simply be rewritten into
where value = 'binary_value'
What changes are included in this PR?
cast_to_sql, which directly pass inner_expr instead of cast inner_expr when casting to binary / dictionary in the Expr::Cast, and keep the original casting logic in all other cases.Are these changes tested?
Yes