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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2022/05/04 07:10:57 UTC
[GitHub] [arrow-datafusion] korowa commented on a diff in pull request #2421: Basic support for `IN` and `NOT IN` Subqueries by rewriting them to `SEMI` / `ANTI`
korowa commented on code in PR #2421:
URL: https://github.com/apache/arrow-datafusion/pull/2421#discussion_r864514634
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datafusion/core/src/optimizer/subquery_filter_to_join.rs:
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@@ -0,0 +1,334 @@
+// 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.
+
+//! Optimizer rule for rewriting subquery filters to joins
+//!
+//! It handles standalone parts of logical conjunction expressions, i.e.
+//! ```text
+//! WHERE t1.f IN (SELECT f FROM t2) AND t2.f = 'x'
+//! ```
+//! will be rewritten, but
+//! ```text
+//! WHERE t1.f IN (SELECT f FROM t2) OR t2.f = 'x'
+//! ```
+//! won't
+use std::sync::Arc;
+
+use crate::error::{DataFusionError, Result};
+use crate::execution::context::ExecutionProps;
+use crate::logical_plan::plan::{Filter, Join};
+use crate::logical_plan::{
+ build_join_schema, Expr, JoinConstraint, JoinType, LogicalPlan,
+};
+use crate::optimizer::optimizer::OptimizerRule;
+use crate::optimizer::utils;
+
+/// Optimizer rule for rewriting subquery filters to joins
+#[derive(Default)]
+pub struct SubqueryFilterToJoin {}
+
+impl SubqueryFilterToJoin {
+ #[allow(missing_docs)]
+ pub fn new() -> Self {
+ Self {}
+ }
+}
+
+impl OptimizerRule for SubqueryFilterToJoin {
+ fn optimize(
+ &self,
+ plan: &LogicalPlan,
+ execution_props: &ExecutionProps,
+ ) -> Result<LogicalPlan> {
+ match plan {
+ LogicalPlan::Filter(Filter { predicate, input }) => {
+ // Apply optimizer rule to current input
+ let optimized_input = self.optimize(input, execution_props)?;
+
+ // Splitting filter expression into components by AND
+ let mut filters = vec![];
+ utils::split_conjunction(predicate, &mut filters);
+
+ // Searching for subquery-based filters
+ let (subquery_filters, regular_filters): (Vec<&Expr>, Vec<&Expr>) =
+ filters
+ .into_iter()
+ .partition(|&e| matches!(e, Expr::InSubquery { .. }));
+
+ // Check all subquery filters could be rewritten
+ //
+ // In case of expressions which could not be rewritten
+ // return original filter with optimized input
+ let mut subqueries_in_regular = vec![];
+ regular_filters.iter().try_for_each(|&e| {
+ extract_subquery_filters(e, &mut subqueries_in_regular)
+ })?;
+
+ if !subqueries_in_regular.is_empty() {
+ return Ok(LogicalPlan::Filter(Filter {
+ predicate: predicate.clone(),
+ input: Arc::new(optimized_input),
+ }));
+ };
+
+ // Add subquery joins to new_input
+ // optimized_input value should retain for possible optimization rollback
+ let opt_result = subquery_filters.iter().try_fold(
+ optimized_input.clone(),
+ |input, &e| match e {
+ Expr::InSubquery {
+ expr,
+ subquery,
+ negated,
+ } => {
+ let right_input = self.optimize(
+ &*subquery.subquery,
+ execution_props
+ )?;
+ let right_schema = right_input.schema();
+ if right_schema.fields().len() != 1 {
+ return Err(DataFusionError::Plan(
+ "Only single column allowed in InSubquery"
+ .to_string(),
+ ));
+ };
+
+ let right_key = right_schema.field(0).qualified_column();
+ let left_key = match *expr.clone() {
+ Expr::Column(col) => col,
+ _ => return Err(DataFusionError::NotImplemented(
+ "Filtering by expression not implemented for InSubquery"
+ .to_string(),
+ )),
+ };
+
+ let join_type = if *negated {
+ JoinType::Anti
+ } else {
+ JoinType::Semi
+ };
+
+ let schema = build_join_schema(
+ optimized_input.schema(),
+ right_schema,
+ &join_type,
+ )?;
+
+ Ok(LogicalPlan::Join(Join {
+ left: Arc::new(input),
+ right: Arc::new(right_input),
+ on: vec![(left_key, right_key)],
+ join_type,
+ join_constraint: JoinConstraint::On,
+ schema: Arc::new(schema),
+ null_equals_null: false,
+ }))
+ }
+ _ => Err(DataFusionError::Plan(
+ "Unknown expression while rewriting subquery to joins"
+ .to_string(),
+ )),
+ }
+ );
+
+ // In case of expressions which could not be rewritten
+ // return original filter with optimized input
+ let new_input = match opt_result {
+ Ok(plan) => plan,
+ Err(_) => {
+ return Ok(LogicalPlan::Filter(Filter {
+ predicate: predicate.clone(),
+ input: Arc::new(optimized_input),
+ }))
+ }
+ };
+
+ // Apply regular filters to join output if some or just return join
+ if regular_filters.is_empty() {
+ Ok(new_input)
+ } else {
+ Ok(utils::add_filter(new_input, ®ular_filters))
+ }
+ }
+ _ => {
+ // Apply the optimization to all inputs of the plan
+ utils::optimize_children(self, plan, execution_props)
+ }
+ }
+ }
+
+ fn name(&self) -> &str {
+ "subquery_filter_to_join"
+ }
+}
+
+fn extract_subquery_filters(expression: &Expr, extracted: &mut Vec<Expr>) -> Result<()> {
+ utils::expr_sub_expressions(expression)?
+ .into_iter()
+ .try_for_each(|se| match se {
+ Expr::InSubquery { .. } => {
+ extracted.push(se);
+ Ok(())
+ }
+ _ => extract_subquery_filters(&se, extracted),
+ })
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use crate::logical_plan::{
+ and, binary_expr, col, in_subquery, lit, not_in_subquery, LogicalPlanBuilder,
+ Operator,
+ };
+ use crate::test::*;
+
+ fn assert_optimized_plan_eq(plan: &LogicalPlan, expected: &str) {
+ let rule = SubqueryFilterToJoin::new();
+ let optimized_plan = rule
+ .optimize(plan, &ExecutionProps::new())
+ .expect("failed to optimize plan");
+ let formatted_plan = format!("{}", optimized_plan.display_indent_schema());
+ assert_eq!(formatted_plan, expected);
+ }
+
+ fn test_subquery() -> Result<Arc<LogicalPlan>> {
+ let table_scan = test_table_scan()?;
+ Ok(Arc::new(
+ LogicalPlanBuilder::from(table_scan)
+ .project(vec![col("c")])?
+ .build()?,
+ ))
+ }
+
+ /// Test for single IN subquery filter
+ #[test]
+ fn in_subquery_simple() -> Result<()> {
+ let table_scan = test_table_scan()?;
+ let plan = LogicalPlanBuilder::from(table_scan)
+ .filter(in_subquery(col("c"), test_subquery()?))?
+ .project(vec![col("test.b")])?
+ .build()?;
+
+ let expected = "Projection: #test.b [b:UInt32]\
+ \n Semi Join: #test.c = #test.c [a:UInt32, b:UInt32, c:UInt32]\
+ \n TableScan: test projection=None [a:UInt32, b:UInt32, c:UInt32]\
+ \n Projection: #test.c [c:UInt32]\
+ \n TableScan: test projection=None [a:UInt32, b:UInt32, c:UInt32]";
+
+ assert_optimized_plan_eq(&plan, expected);
+ Ok(())
+ }
+
+ /// Test for single NOT IN subquery filter
+ #[test]
+ fn not_in_subquery_simple() -> Result<()> {
+ let table_scan = test_table_scan()?;
+ let plan = LogicalPlanBuilder::from(table_scan)
+ .filter(not_in_subquery(col("c"), test_subquery()?))?
+ .project(vec![col("test.b")])?
+ .build()?;
+
+ let expected = "Projection: #test.b [b:UInt32]\
+ \n Anti Join: #test.c = #test.c [a:UInt32, b:UInt32, c:UInt32]\
Review Comment:
Done - now table names in tests are different, so it should by much easier to read
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