xudong963 commented on code in PR #2858: URL: https://github.com/apache/arrow-datafusion/pull/2858#discussion_r917950725
########## datafusion/optimizer/src/rewrite_disjunctive_predicate.rs: ########## @@ -0,0 +1,468 @@ +// 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::{ + Aggregate, Analyze, CreateMemoryTable, CreateView, CrossJoin, Distinct, Explain, + Filter, Join, Limit, Projection, Repartition, Sort, Subquery, SubqueryAlias, Union, + Window, +}; +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 + for or_predicate in or_predicates.iter() { + match or_predicate { + Predicate::And { args } => { + let args_num = args.len(); + if shortest_exprs.is_empty() || args_num < shortest_exprs_len { + shortest_exprs = (*args).clone(); + shortest_exprs_len = args_num; + } + } + _ => { + // if there is no AND predicate, it must be the shortest expression. + shortest_exprs = vec![or_predicate.clone()]; + break; + } + } + } + + // dedup shortest_exprs + shortest_exprs.dedup(); + + // Check each element in shortest_exprs to see if it's in all the OR arguments. + let mut exist_exprs: Vec<Predicate> = vec![]; + for expr in shortest_exprs.iter() { + let mut found = true; + for or_predicate in or_predicates.iter() { + match or_predicate { + Predicate::And { args } => { + if !args.contains(expr) { + found = false; + break; + } + } + _ => { + if or_predicate != expr { + found = false; + break; + } + } + } + } + if found { + exist_exprs.push((*expr).clone()); + } + } + if exist_exprs.is_empty() { + return Predicate::Or { + args: or_predicates.to_vec(), + }; + } + + // Rebuild the OR predicate. + // (A AND B) OR A will be optimized to A. + let mut new_or_predicates = vec![]; + for or_predicate in or_predicates.iter() { + match or_predicate { + Predicate::And { args } => { + let mut new_args = (*args).clone(); + new_args.retain(|expr| !exist_exprs.contains(expr)); + if !new_args.is_empty() { + if new_args.len() == 1 { + new_or_predicates.push(new_args[0].clone()); + } else { + new_or_predicates.push(Predicate::And { args: new_args }); + } + } else { + new_or_predicates.clear(); + break; + } + } + _ => { + if exist_exprs.contains(or_predicate) { + new_or_predicates.clear(); + break; + } + } + } + } + if !new_or_predicates.is_empty() { + if new_or_predicates.len() == 1 { + exist_exprs.push(new_or_predicates[0].clone()); + } else { + exist_exprs.push(Predicate::Or { + args: flatten_or_predicates(&new_or_predicates), + }); + } + } + + if exist_exprs.len() == 1 { + exist_exprs[0].clone() + } else { + Predicate::And { + args: flatten_and_predicates(&exist_exprs), + } + } +} + +#[derive(Default)] +pub struct RewriteDisjunctivePredicate; + +impl RewriteDisjunctivePredicate { + pub fn new() -> Self { + Self::default() + } + fn rewrite_disjunctive_predicate( + &self, + plan: &LogicalPlan, + _optimizer_config: &OptimizerConfig, + ) -> Result<LogicalPlan> { + match plan { + LogicalPlan::Filter(filter) => { Review Comment: It seems to be new interfaces for `LogicalPlan` added during my absence, I would have liked to add similar interfaces after this ticket, because I was tired of writing here 🤣 -- This is an automated message from the Apache Git Service. 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