jgoday commented on a change in pull request #436: URL: https://github.com/apache/arrow-datafusion/pull/436#discussion_r643818548
########## File path: datafusion/src/optimizer/simplify_expressions.rs ########## @@ -0,0 +1,506 @@ +// 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. + +//! Remove duplicate filters optimizer rule + +use crate::execution::context::ExecutionProps; +use crate::logical_plan::LogicalPlan; +use crate::logical_plan::{lit, Expr}; +use crate::optimizer::optimizer::OptimizerRule; +use crate::optimizer::utils; +use crate::optimizer::utils::optimize_explain; +use crate::scalar::ScalarValue; +use crate::{error::Result, logical_plan::Operator}; + +/// Simplify expressions optimizer. +/// # Introduction +/// It uses boolean algebra laws to simplify or reduce the number of terms in expressions. +/// +/// Filter: b > 2 AND b > 2 +/// is optimized to +/// Filter: b > 2 +pub struct SimplifyExpressions {} + +fn expr_contains(expr: &Expr, needle: &Expr) -> bool { + match expr { + Expr::BinaryExpr { + left, + op: Operator::And, + right, + } => expr_contains(left, needle) || expr_contains(right, needle), + Expr::BinaryExpr { + left, + op: Operator::Or, + right, + } => expr_contains(left, needle) || expr_contains(right, needle), + _ => expr == needle, + } +} + +fn as_binary_expr(expr: &Expr) -> Option<&Expr> { + match expr { + Expr::BinaryExpr { .. } => Some(expr), + _ => None, + } +} + +fn operator_is_boolean(op: Operator) -> bool { + op == Operator::And || op == Operator::Or +} + +fn is_one(s: &Expr) -> bool { + match s { + Expr::Literal(ScalarValue::Int8(Some(1))) + | Expr::Literal(ScalarValue::Int16(Some(1))) + | Expr::Literal(ScalarValue::Int32(Some(1))) + | Expr::Literal(ScalarValue::Int64(Some(1))) + | Expr::Literal(ScalarValue::UInt8(Some(1))) + | Expr::Literal(ScalarValue::UInt16(Some(1))) + | Expr::Literal(ScalarValue::UInt32(Some(1))) + | Expr::Literal(ScalarValue::UInt64(Some(1))) => true, + Expr::Literal(ScalarValue::Float32(Some(v))) if *v == 1. => true, + Expr::Literal(ScalarValue::Float64(Some(v))) if *v == 1. => true, + _ => false, + } +} + +fn is_true(expr: &Expr) -> bool { + match expr { + Expr::Literal(ScalarValue::Boolean(Some(v))) => *v, + _ => false, + } +} + +fn is_false(expr: &Expr) -> bool { + match expr { + Expr::Literal(ScalarValue::Boolean(Some(v))) => *v == false, + _ => false, + } +} + +fn simplify(expr: &Expr) -> Expr { + match expr { + Expr::BinaryExpr { + left, + op: Operator::Or, + right, + } if is_true(left) || is_true(right) => lit(true), + Expr::BinaryExpr { + left, + op: Operator::Or, + right, + } if is_false(left) => simplify(right), + Expr::BinaryExpr { + left, + op: Operator::Or, + right, + } if is_false(right) => simplify(left), + Expr::BinaryExpr { + left, + op: Operator::Or, + right, + } if left == right => simplify(left), + Expr::BinaryExpr { + left, + op: Operator::And, + right, + } if is_false(left) || is_false(right) => lit(false), + Expr::BinaryExpr { + left, + op: Operator::And, + right, + } if is_true(right) => simplify(left), + Expr::BinaryExpr { + left, + op: Operator::And, + right, + } if is_true(left) => simplify(right), + Expr::BinaryExpr { + left, + op: Operator::And, + right, + } if left == right => simplify(right), + Expr::BinaryExpr { + left, + op: Operator::Multiply, + right, + } if is_one(left) => simplify(right), + Expr::BinaryExpr { + left, + op: Operator::Multiply, + right, + } if is_one(right) => simplify(left), + Expr::BinaryExpr { + left, + op: Operator::Divide, + right, + } if is_one(right) => simplify(left), + Expr::BinaryExpr { + left, + op: Operator::Divide, + right, + } if left == right => lit(1), + Expr::BinaryExpr { left, op, right } + if left == right && operator_is_boolean(*op) => + { + simplify(left) + } + Expr::BinaryExpr { + left, + op: Operator::Or, + right, + } if expr_contains(left, right) => as_binary_expr(left) Review comment: I think that is needed for expressions like '((c > 5) AND (d < 6)) AND (c > 5)'. Nested simplification should be fixed by latest commit. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
