Remove logical cross join in planning

datafusion/core/src/physical_planner.rs

@@ -78,7 +78,7 @@ use datafusion_expr::expr::{
 use datafusion_expr::expr_rewriter::unnormalize_cols;
 use datafusion_expr::logical_plan::builder::wrap_projection_for_join_if_necessary;
 use datafusion_expr::{
-    DescribeTable, DmlStatement, Extension, Filter, RecursiveQuery, SortExpr,
+    DescribeTable, DmlStatement, Extension, Filter, JoinType, RecursiveQuery, SortExpr,
     StringifiedPlan, WindowFrame, WindowFrameBound, WriteOp,
 };
 use datafusion_physical_expr::aggregate::{AggregateExprBuilder, AggregateFunctionExpr};
@@ -1045,14 +1045,18 @@ impl DefaultPhysicalPlanner {
                     session_state.config_options().optimizer.prefer_hash_join;
 
                 let join: Arc<dyn ExecutionPlan> = if join_on.is_empty() {
-                    // there is no equal join condition, use the nested loop join
-                    // TODO optimize the plan, and use the config of `target_partitions` and `repartition_joins`
-                    Arc::new(NestedLoopJoinExec::try_new(
-                        physical_left,
-                        physical_right,
-                        join_filter,
-                        join_type,
-                    )?)
+                    if join_filter.is_none() && matches!(join_type, JoinType::Inner) {
+                        // cross join if there is no join conditions and no join filter set
+                        Arc::new(CrossJoinExec::new(physical_left, physical_right))
+                    } else {
+                        // there is no equal join condition, use the nested loop join
+                        Arc::new(NestedLoopJoinExec::try_new(
+                            physical_left,
+                            physical_right,
+                            join_filter,
+                            join_type,
+                        )?)
+                    }
                 } else if session_state.config().target_partitions() > 1
                     && session_state.config().repartition_joins()
                     && !prefer_hash_join

datafusion/expr/src/logical_plan/builder.rs

@@ -30,8 +30,8 @@ use crate::expr_rewriter::{
     rewrite_sort_cols_by_aggs,
 };
 use crate::logical_plan::{
-    Aggregate, Analyze, CrossJoin, Distinct, DistinctOn, EmptyRelation, Explain, Filter,
-    Join, JoinConstraint, JoinType, Limit, LogicalPlan, Partitioning, PlanType, Prepare,
+    Aggregate, Analyze, Distinct, DistinctOn, EmptyRelation, Explain, Filter, Join,
+    JoinConstraint, JoinType, Limit, LogicalPlan, Partitioning, PlanType, Prepare,
     Projection, Repartition, Sort, SubqueryAlias, TableScan, Union, Unnest, Values,
     Window,
 };
@@ -950,9 +950,14 @@ impl LogicalPlanBuilder {
     pub fn cross_join(self, right: LogicalPlan) -> Result<Self> {
         let join_schema =
             build_join_schema(self.plan.schema(), right.schema(), &JoinType::Inner)?;
-        Ok(Self::new(LogicalPlan::CrossJoin(CrossJoin {
+        Ok(Self::new(LogicalPlan::Join(Join {
             left: self.plan,
             right: Arc::new(right),
+            on: vec![],
+            filter: None,
+            join_type: JoinType::Inner,
+            join_constraint: JoinConstraint::On,
+            null_equals_null: false,
             schema: DFSchemaRef::new(join_schema),
         })))
     }

datafusion/expr/src/logical_plan/plan.rs

@@ -222,6 +222,7 @@ pub enum LogicalPlan {
     Join(Join),
     /// Apply Cross Join to two logical plans.
     /// This is used to implement SQL `CROSS JOIN`
+    /// Deprecated: use [LogicalPlan::Join] instead with empty `on` / no filter
     CrossJoin(CrossJoin),
     /// Repartitions the input based on a partitioning scheme. This is
     /// used to add parallelism and is sometimes referred to as an
@@ -1873,6 +1874,11 @@ impl LogicalPlan {
                             .as_ref()
                             .map(|expr| format!(" Filter: {expr}"))
                             .unwrap_or_else(|| "".to_string());
+                        let join_type = if filter.is_none() && keys.is_empty() && matches!(join_type, JoinType::Inner) {
+                            "Cross".to_string()
+                        } else {
+                            join_type.to_string()
+                        };
                         match join_constraint {
                             JoinConstraint::On => {
                                 write!(

datafusion/optimizer/src/eliminate_cross_join.rs

@@ -25,7 +25,7 @@ use datafusion_common::tree_node::{Transformed, TreeNode};
 use datafusion_common::{internal_err, Result};
 use datafusion_expr::expr::{BinaryExpr, Expr};
 use datafusion_expr::logical_plan::{
-    CrossJoin, Filter, Join, JoinConstraint, JoinType, LogicalPlan, Projection,
+    Filter, Join, JoinConstraint, JoinType, LogicalPlan, Projection,
 };
 use datafusion_expr::utils::{can_hash, find_valid_equijoin_key_pair};
 use datafusion_expr::{build_join_schema, ExprSchemable, Operator};
@@ -51,7 +51,7 @@ impl EliminateCrossJoin {
 /// Looks like this:
 /// ```text
 /// Filter(a.x = b.y AND b.xx = 100)
-///  CrossJoin
+///  Cross Join
 ///   TableScan a
 ///   TableScan b
 /// ```
@@ -351,10 +351,15 @@ fn find_inner_join(
         &JoinType::Inner,
     )?);
 
-    Ok(LogicalPlan::CrossJoin(CrossJoin {
+    Ok(LogicalPlan::Join(Join {
         left: Arc::new(left_input),
         right: Arc::new(right),
         schema: join_schema,
+        on: vec![],
+        filter: None,
+        join_type: JoinType::Inner,
+        join_constraint: JoinConstraint::On,
+        null_equals_null: false,
     }))
 }
 
@@ -513,7 +518,7 @@ mod tests {
 
         let expected = vec![
             "Filter: t1.a = t2.a OR t2.b = t1.a [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
-            "  CrossJoin: [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
+            "  Cross Join:  [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "    TableScan: t1 [a:UInt32, b:UInt32, c:UInt32]",
             "    TableScan: t2 [a:UInt32, b:UInt32, c:UInt32]",
         ];
@@ -601,7 +606,7 @@ mod tests {
 
         let expected = vec![
             "Filter: t1.a = t2.a AND t2.c < UInt32(15) OR t1.b = t2.b AND t2.c = UInt32(688) [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
-            "  CrossJoin: [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
+            "  Cross Join:  [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "    TableScan: t1 [a:UInt32, b:UInt32, c:UInt32]",
             "    TableScan: t2 [a:UInt32, b:UInt32, c:UInt32]",
         ];
@@ -627,7 +632,7 @@ mod tests {
 
         let expected = vec![
             "Filter: t1.a = t2.a AND t2.c < UInt32(15) OR t1.a = t2.a OR t2.c = UInt32(688) [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
-            "  CrossJoin: [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
+            "  Cross Join:  [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "    TableScan: t1 [a:UInt32, b:UInt32, c:UInt32]",
             "    TableScan: t2 [a:UInt32, b:UInt32, c:UInt32]",
         ];
@@ -843,7 +848,7 @@ mod tests {
 
         let expected = vec![
             "Filter: t3.a = t1.a AND t4.c < UInt32(15) OR t3.a = t1.a OR t4.c = UInt32(688) [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
-            "  CrossJoin: [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
+            "  Cross Join:  [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "    Filter: t2.c < UInt32(15) OR t2.c = UInt32(688) [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "      Inner Join: t1.a = t2.a [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "        TableScan: t1 [a:UInt32, b:UInt32, c:UInt32]",
@@ -924,7 +929,7 @@ mod tests {
             "        TableScan: t1 [a:UInt32, b:UInt32, c:UInt32]",
             "        TableScan: t2 [a:UInt32, b:UInt32, c:UInt32]",
             "    Filter: t3.a = t4.a AND t4.c < UInt32(15) OR t3.a = t4.a AND t3.c = UInt32(688) OR t3.a = t4.a OR t3.b = t4.b [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
-            "      CrossJoin: [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
+            "      Cross Join:  [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "        TableScan: t3 [a:UInt32, b:UInt32, c:UInt32]",
             "        TableScan: t4 [a:UInt32, b:UInt32, c:UInt32]",
         ];
@@ -999,7 +1004,7 @@ mod tests {
             "Filter: t4.c < UInt32(15) OR t4.c = UInt32(688) [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "  Inner Join: t1.a = t3.a [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "    Filter: t1.a = t2.a OR t2.c < UInt32(15) OR t1.a = t2.a AND t2.c = UInt32(688) [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
-            "      CrossJoin: [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
+            "      Cross Join:  [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
             "        TableScan: t1 [a:UInt32, b:UInt32, c:UInt32]",
             "        TableScan: t2 [a:UInt32, b:UInt32, c:UInt32]",
             "    Filter: t4.c < UInt32(15) OR t3.c = UInt32(688) OR t3.b = t4.b [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
@@ -1238,7 +1243,7 @@ mod tests {
 
         let expected = vec![
               "Filter: t1.a + UInt32(100) = t2.a * UInt32(2) OR t2.b = t1.a [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
-              "  CrossJoin: [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
+              "  Cross Join:  [a:UInt32, b:UInt32, c:UInt32, a:UInt32, b:UInt32, c:UInt32]",
               "    TableScan: t1 [a:UInt32, b:UInt32, c:UInt32]",
               "    TableScan: t2 [a:UInt32, b:UInt32, c:UInt32]",
         ];

datafusion/optimizer/src/eliminate_join.rs

@@ -23,7 +23,7 @@ use datafusion_common::{Result, ScalarValue};
 use datafusion_expr::JoinType::Inner;
 use datafusion_expr::{
     logical_plan::{EmptyRelation, LogicalPlan},
-    CrossJoin, Expr,
+    Expr,
 };
 
 /// Eliminates joins when join condition is false.
@@ -54,13 +54,6 @@ impl OptimizerRule for EliminateJoin {
         match plan {
             LogicalPlan::Join(join) if join.join_type == Inner && join.on.is_empty() => {
                 match join.filter {
-                    Some(Expr::Literal(ScalarValue::Boolean(Some(true)))) => {
-                        Ok(Transformed::yes(LogicalPlan::CrossJoin(CrossJoin {
-                            left: join.left,
-                            right: join.right,
-                            schema: join.schema,
-                        })))
-                    }
                     Some(Expr::Literal(ScalarValue::Boolean(Some(false)))) => Ok(
                         Transformed::yes(LogicalPlan::EmptyRelation(EmptyRelation {
                             produce_one_row: false,
@@ -105,21 +98,4 @@ mod tests {
         let expected = "EmptyRelation";
         assert_optimized_plan_equal(plan, expected)
     }
-
-    #[test]
-    fn join_on_true() -> Result<()> {
-        let plan = LogicalPlanBuilder::empty(false)
-            .join_on(
-                LogicalPlanBuilder::empty(false).build()?,
-                Inner,
-                Some(lit(true)),
-            )?
-            .build()?;
-
-        let expected = "\
-        CrossJoin:\
-        \n  EmptyRelation\
-        \n  EmptyRelation";
-        assert_optimized_plan_equal(plan, expected)
-    }
 }

datafusion/optimizer/src/push_down_filter.rs

@@ -1727,7 +1727,7 @@ mod tests {
             .build()?;
 
         let expected = "Projection: test.a, test1.d\
-        \n  CrossJoin:\
+        \n  Cross Join: \
         \n    Projection: test.a, test.b, test.c\
         \n      TableScan: test, full_filters=[test.a = Int32(1)]\
         \n    Projection: test1.d, test1.e, test1.f\
@@ -1754,7 +1754,7 @@ mod tests {
             .build()?;
 
         let expected = "Projection: test.a, test1.a\
-        \n  CrossJoin:\
+        \n  Cross Join: \
         \n    Projection: test.a, test.b, test.c\
         \n      TableScan: test, full_filters=[test.a = Int32(1)]\
         \n    Projection: test1.a, test1.b, test1.c\

datafusion/optimizer/src/push_down_limit.rs

@@ -254,10 +254,9 @@ fn push_down_join(mut join: Join, limit: usize) -> Transformed<Join> {
 
     let (left_limit, right_limit) = if is_no_join_condition(&join) {
         match join.join_type {
-            Left | Right | Full => (Some(limit), Some(limit)),
+            Left | Right | Full | Inner => (Some(limit), Some(limit)),
             LeftAnti | LeftSemi => (Some(limit), None),
             RightAnti | RightSemi => (None, Some(limit)),
-            Inner => (None, None),
         }
     } else {
         match join.join_type {
@@ -1116,7 +1115,7 @@ mod test {
             .build()?;
 
         let expected = "Limit: skip=0, fetch=1000\
-        \n  CrossJoin:\
+        \n  Cross Join: \
         \n    Limit: skip=0, fetch=1000\
         \n      TableScan: test, fetch=1000\
         \n    Limit: skip=0, fetch=1000\
@@ -1136,7 +1135,7 @@ mod test {
             .build()?;
 
         let expected = "Limit: skip=1000, fetch=1000\
-        \n  CrossJoin:\
+        \n  Cross Join: \
         \n    Limit: skip=0, fetch=2000\
         \n      TableScan: test, fetch=2000\
         \n    Limit: skip=0, fetch=2000\

datafusion/sql/src/relation/join.rs

@@ -151,7 +151,9 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
                         .build()
                 }
             }
-            JoinConstraint::None => not_impl_err!("NONE constraint is not supported"),
+            JoinConstraint::None => LogicalPlanBuilder::from(left)
+                .join_on(right, join_type, [])?
+                .build(),
         }
     }
 }

datafusion/sql/tests/cases/plan_to_sql.rs

@@ -243,7 +243,7 @@ fn roundtrip_crossjoin() -> Result<()> {
         .unwrap();
 
     let expected = "Projection: j1.j1_id, j2.j2_string\
-        \n  Inner Join:  Filter: Boolean(true)\
+        \n  Cross Join: \
         \n    TableScan: j1\
         \n    TableScan: j2";