xudong963 commented on code in PR #2858: URL: https://github.com/apache/arrow-datafusion/pull/2858#discussion_r929981363
########## datafusion/optimizer/src/rewrite_disjunctive_predicate.rs: ########## @@ -0,0 +1,429 @@ +// 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 crate::{OptimizerConfig, OptimizerRule}; +use datafusion_common::Result; +use datafusion_expr::logical_plan::Filter; +use datafusion_expr::utils::from_plan; +use datafusion_expr::Expr::BinaryExpr; +use datafusion_expr::{Expr, LogicalPlan, Operator}; +use std::sync::Arc; + +#[derive(Clone, PartialEq, Debug)] +enum Predicate { + And { args: Vec<Predicate> }, + Or { args: Vec<Predicate> }, + Other { expr: Box<Expr> }, +} + +fn predicate(expr: &Expr) -> Result<Predicate> { + match expr { + BinaryExpr { left, op, right } => match op { + Operator::And => { + let args = vec![predicate(left)?, predicate(right)?]; + Ok(Predicate::And { args }) + } + Operator::Or => { + let args = vec![predicate(left)?, predicate(right)?]; + Ok(Predicate::Or { args }) + } + _ => Ok(Predicate::Other { + expr: Box::new(BinaryExpr { + left: left.clone(), + op: *op, + right: right.clone(), + }), + }), + }, + _ => Ok(Predicate::Other { + expr: Box::new(expr.clone()), + }), + } +} + +fn normalize_predicate(predicate: &Predicate) -> Expr { + match predicate { + Predicate::And { args } => { + assert!(args.len() >= 2); + let left = normalize_predicate(&args[0]); + let right = normalize_predicate(&args[1]); + let mut and_expr = BinaryExpr { + left: Box::new(left), + op: Operator::And, + right: Box::new(right), + }; + for arg in args.iter().skip(2) { + and_expr = BinaryExpr { + left: Box::new(and_expr), + op: Operator::And, + right: Box::new(normalize_predicate(arg)), + }; + } + and_expr + } + Predicate::Or { args } => { + assert!(args.len() >= 2); + let left = normalize_predicate(&args[0]); + let right = normalize_predicate(&args[1]); + let mut or_expr = BinaryExpr { + left: Box::new(left), + op: Operator::Or, + right: Box::new(right), + }; + for arg in args.iter().skip(2) { + or_expr = BinaryExpr { + left: Box::new(or_expr), + op: Operator::Or, + right: Box::new(normalize_predicate(arg)), + }; + } + or_expr + } + Predicate::Other { expr } => *expr.clone(), + } +} + +fn rewrite_predicate(predicate: &Predicate) -> Predicate { + match predicate { + Predicate::And { args } => { + let mut rewritten_args = Vec::with_capacity(args.len()); + for arg in args.iter() { + rewritten_args.push(rewrite_predicate(arg)); + } + rewritten_args = flatten_and_predicates(&rewritten_args); + Predicate::And { + args: rewritten_args, + } + } + Predicate::Or { args } => { + let mut rewritten_args = vec![]; + for arg in args.iter() { + rewritten_args.push(rewrite_predicate(arg)); + } + rewritten_args = flatten_or_predicates(&rewritten_args); + delete_duplicate_predicates(&rewritten_args) + } + Predicate::Other { expr } => Predicate::Other { + expr: Box::new(*expr.clone()), + }, + } +} + +fn flatten_and_predicates(and_predicates: &[Predicate]) -> Vec<Predicate> { + let mut flattened_predicates = vec![]; + for predicate in and_predicates { + match predicate { + Predicate::And { args } => { + flattened_predicates + .extend_from_slice(flatten_and_predicates(args).as_slice()); + } + _ => { + flattened_predicates.push(predicate.clone()); + } + } + } + flattened_predicates +} + +fn flatten_or_predicates(or_predicates: &[Predicate]) -> Vec<Predicate> { + let mut flattened_predicates = vec![]; + for predicate in or_predicates { + match predicate { + Predicate::Or { args } => { + flattened_predicates + .extend_from_slice(flatten_or_predicates(args).as_slice()); + } + _ => { + flattened_predicates.push(predicate.clone()); + } + } + } + flattened_predicates +} + +fn delete_duplicate_predicates(or_predicates: &[Predicate]) -> Predicate { + let mut shortest_exprs: Vec<Predicate> = vec![]; + let mut shortest_exprs_len = 0; + // choose the shortest AND predicate Review Comment: > For example, in the following predicate, the common sub expression`(p_partkey = l_partkey OR p_partkey > 5)` is not the shortest The common sub-expression is from the shortest AND predicate, but the shortest AND predicate is not equal to the common sub-expression(beside each element in the shortest AND predicate is in all the OR arguments.) -- This is an automated message from the Apache Git Service. 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