2010YOUY01 commented on code in PR #18789:
URL: https://github.com/apache/datafusion/pull/18789#discussion_r2544175337
##########
datafusion/optimizer/src/simplify_expressions/expr_simplifier.rs:
##########
@@ -1956,6 +1962,36 @@ impl<S: SimplifyInfo> TreeNodeRewriter for
Simplifier<'_, S> {
}))
}
+ // =======================================
+ // unwrap_date_part_in_comparison
+ // =======================================
+ //
+ // For case:
+ // date_part(expr as data_type) op literal
+ Expr::BinaryExpr(BinaryExpr { left, op, right })
Review Comment:
```suggestion
//
// Background:
// Datasources such as Parquet can prune partitions using simple
predicates,
// but they cannot do so for complex expressions.
// For a complex predicate like `date_part('YEAR', c1) < 2000`,
pruning is not possible.
// After rewriting it to `c1 < 2000-01-01`, pruning becomes
feasible.
Expr::BinaryExpr(BinaryExpr { left, op, right })
```
##########
datafusion/optimizer/src/simplify_expressions/unwrap_date_part.rs:
##########
@@ -0,0 +1,371 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+use arrow::datatypes::{DataType, TimeUnit};
+use chrono::NaiveDate;
+use datafusion_common::{
+ internal_err, tree_node::Transformed, DataFusionError, Result, ScalarValue,
+};
+use datafusion_expr::{
+ and, expr::ScalarFunction, lit, or, simplify::SimplifyInfo, BinaryExpr,
Expr,
+ Operator,
+};
+
+pub(super) fn unwrap_date_part_in_comparison_for_binary<S: SimplifyInfo>(
+ info: &S,
+ cast_expr: Expr,
+ literal: Expr,
+ op: Operator,
+) -> Result<Transformed<Expr>> {
+ let (args, lit_value) = match (cast_expr, literal) {
+ (
+ Expr::ScalarFunction(ScalarFunction { func, args }),
+ Expr::Literal(lit_value, _),
+ ) if func.name() == "date_part" => (args, lit_value),
Review Comment:
I wish we can have a safer way to check it in the future. Related:
https://github.com/apache/datafusion/issues/18643
##########
datafusion/optimizer/src/simplify_expressions/unwrap_date_part.rs:
##########
@@ -0,0 +1,371 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+use arrow::datatypes::{DataType, TimeUnit};
+use chrono::NaiveDate;
+use datafusion_common::{
+ internal_err, tree_node::Transformed, DataFusionError, Result, ScalarValue,
+};
+use datafusion_expr::{
+ and, expr::ScalarFunction, lit, or, simplify::SimplifyInfo, BinaryExpr,
Expr,
+ Operator,
+};
+
+pub(super) fn unwrap_date_part_in_comparison_for_binary<S: SimplifyInfo>(
+ info: &S,
+ cast_expr: Expr,
+ literal: Expr,
+ op: Operator,
+) -> Result<Transformed<Expr>> {
+ let (args, lit_value) = match (cast_expr, literal) {
+ (
+ Expr::ScalarFunction(ScalarFunction { func, args }),
+ Expr::Literal(lit_value, _),
+ ) if func.name() == "date_part" => (args, lit_value),
+ _ => return internal_err!("Expect date_part expr and literal"),
+ };
+ let expr = Box::new(args[1].clone());
+
+ let Ok(expr_type) = info.get_data_type(&expr) else {
+ return internal_err!("Can't get the data type of the expr {:?}",
&expr);
+ };
+
+ // Helper to cast literal
+ let cast_year = |updated_year: &ScalarValue| -> Result<ScalarValue,
DataFusionError> {
+ year_literal_to_type(updated_year, &expr_type).ok_or_else(|| {
+ DataFusionError::Internal(format!(
Review Comment:
nit: I think macro `internal_datafusion_err!` can be used here.
##########
datafusion/optimizer/src/simplify_expressions/expr_simplifier.rs:
##########
@@ -1956,6 +1962,36 @@ impl<S: SimplifyInfo> TreeNodeRewriter for
Simplifier<'_, S> {
}))
}
+ // =======================================
+ // unwrap_date_part_in_comparison
+ // =======================================
+ //
+ // For case:
+ // date_part(expr as data_type) op literal
Review Comment:
It would be great to specify all the supported patterns here, like only
extracting years, and what's the supported `op` and `literal` types.
##########
datafusion/optimizer/src/simplify_expressions/expr_simplifier.rs:
##########
@@ -1956,6 +1962,36 @@ impl<S: SimplifyInfo> TreeNodeRewriter for
Simplifier<'_, S> {
}))
}
+ // =======================================
+ // unwrap_date_part_in_comparison
+ // =======================================
+ //
+ // For case:
+ // date_part(expr as data_type) op literal
+ Expr::BinaryExpr(BinaryExpr { left, op, right })
+ if
is_date_part_expr_and_support_unwrap_date_part_in_comparison_for_binary(
+ info, &left, op, &right,
+ ) && op.supports_propagation() =>
Review Comment:
I don't get the purpose of `supports_propagation()` here, after reading its
source comments. Perhaps we can improve the documentation later.
##########
datafusion/optimizer/src/simplify_expressions/expr_simplifier.rs:
##########
@@ -1956,6 +1962,36 @@ impl<S: SimplifyInfo> TreeNodeRewriter for
Simplifier<'_, S> {
}))
}
+ // =======================================
Review Comment:
First to make sure I get the issue correctly:
- The current `ScalarUDFImpl::simplify()` is not working, because it's
recognizing patterns that the scalar function is the expression root, and swap
this scalar function root to any other equivalent expression
- Because we're rewriting expressions like `EXTRACT (YEAR FROM k) = 2024`,
its expr tree root node is `=`. If a similar `simplify()` API is available on
operators like `=`, then we can implement such rewrite easier.
Probably we can refactor all the operators like `+, -, <` to use `ScalarUDF`
interface? Fundamentally they're the all a node in the expression tree.
The refactoring process can get a bit painful, but it's appealing to see a
unified interface for all the expressions in the long term.
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