From 7e7f7732145fd87888291661dcb40464fecf29eb Mon Sep 17 00:00:00 2001
From: Davis Haupt <davis.haupt@mongodb.com>
Date: Wed, 11 Jan 2023 14:59:07 +0000
Subject: SERVER-72312 Add lowering unittest for NestedLoopJoinNode

---
 src/mongo/db/exec/sbe/abt/abt_lower_test.cpp       | 33 +++++++++
 src/mongo/db/exec/sbe/stages/loop_join.cpp         | 12 ++++
 .../lower_nested_loop_join_node.txt                | 79 ++++++++++++++++++++++
 3 files changed, 124 insertions(+)
 create mode 100644 src/mongo/db/test_output/exec/sbe/a_b_t_plan_generation/lower_nested_loop_join_node.txt

(limited to 'src/mongo/db')

diff --git a/src/mongo/db/exec/sbe/abt/abt_lower_test.cpp b/src/mongo/db/exec/sbe/abt/abt_lower_test.cpp
index 206a7f93502..74a094a3470 100644
--- a/src/mongo/db/exec/sbe/abt/abt_lower_test.cpp
+++ b/src/mongo/db/exec/sbe/abt/abt_lower_test.cpp
@@ -482,6 +482,39 @@ TEST_F(ABTPlanGeneration, LowerMergeJoinNode) {
     }
 }
 
+TEST_F(ABTPlanGeneration, LowerNestedLoopJoinNode) {
+    GoldenTestContext ctx(&goldenTestConfig);
+    ctx.printTestHeader(GoldenTestContext::HeaderFormat::Text);
+
+    // Run a variation for both supported join types.
+    std::vector<JoinType> joins = {JoinType::Inner, JoinType::Left};
+    for (auto& joinType : joins) {
+        auto child1 = createBindings(
+            {{"city", "proj0"}},
+            _node(make<PhysicalScanNode>(
+                FieldProjectionMap{{}, {ProjectionName{"scan0"}}, {}}, "collName", false)),
+            "scan0");
+        auto child2 = createBindings(
+            {{"id", "proj1"}},
+            _node(make<PhysicalScanNode>(
+                FieldProjectionMap{{}, {ProjectionName{"scan1"}}, {}}, "otherColl", false)),
+            "scan1");
+
+        runNodeVariation(
+            ctx,
+            str::stream() << "Nested loop join with equality predicate ("
+                          << JoinTypeEnum::toString[static_cast<int>(joinType)] << " join)",
+            _node(make<NestedLoopJoinNode>(
+                joinType,
+                ProjectionNameSet{"proj0"},
+                _path(make<EvalFilter>(
+                    make<PathCompare>(Operations::Eq, make<Variable>(ProjectionName{"proj1"})),
+                    make<Variable>(ProjectionName{"proj0"}))),
+                std::move(child1),
+                std::move(child2))));
+    }
+}
+
 TEST_F(ABTPlanGeneration, LowerPhysicalScanNode) {
     GoldenTestContext ctx(&goldenTestConfig);
     ctx.printTestHeader(GoldenTestContext::HeaderFormat::Text);
diff --git a/src/mongo/db/exec/sbe/stages/loop_join.cpp b/src/mongo/db/exec/sbe/stages/loop_join.cpp
index 123faa7daf5..8bff1012bca 100644
--- a/src/mongo/db/exec/sbe/stages/loop_join.cpp
+++ b/src/mongo/db/exec/sbe/stages/loop_join.cpp
@@ -244,6 +244,18 @@ const SpecificStats* LoopJoinStage::getSpecificStats() const {
 std::vector<DebugPrinter::Block> LoopJoinStage::debugPrint() const {
     auto ret = PlanStage::debugPrint();
 
+    switch (_joinType) {
+        case JoinType::Inner:
+            ret.emplace_back(DebugPrinter::Block("inner"));
+            break;
+        case JoinType::Left:
+            ret.emplace_back(DebugPrinter::Block("left"));
+            break;
+        case JoinType::Right:
+            ret.emplace_back(DebugPrinter::Block("right"));
+            break;
+    }
+
     ret.emplace_back(DebugPrinter::Block("[`"));
     for (size_t idx = 0; idx < _outerProjects.size(); ++idx) {
         if (idx) {
diff --git a/src/mongo/db/test_output/exec/sbe/a_b_t_plan_generation/lower_nested_loop_join_node.txt b/src/mongo/db/test_output/exec/sbe/a_b_t_plan_generation/lower_nested_loop_join_node.txt
new file mode 100644
index 00000000000..29764e12e1c
--- /dev/null
+++ b/src/mongo/db/test_output/exec/sbe/a_b_t_plan_generation/lower_nested_loop_join_node.txt
@@ -0,0 +1,79 @@
+# Golden test output of ABTPlanGeneration/LowerNestedLoopJoinNode
+
+==== VARIATION: Nested loop join with equality predicate (Inner join) ====
+-- INPUT:
+NestedLoopJoin [joinType: Inner, {proj0}]
+|   |   BinaryOp [FillEmpty]
+|   |   |   Const [false]
+|   |   BinaryOp [Eq]
+|   |   |   Variable [proj1]
+|   |   Variable [proj0]
+|   Evaluation []
+|   |   BindBlock:
+|   |       [proj1]
+|   |           FunctionCall [getField]
+|   |           |   Const ["id"]
+|   |           Variable [scan1]
+|   PhysicalScan [{'<root>': scan1}, otherColl]
+|       BindBlock:
+|           [scan1]
+|               Source []
+Evaluation []
+|   BindBlock:
+|       [proj0]
+|           FunctionCall [getField]
+|           |   Const ["city"]
+|           Variable [scan0]
+PhysicalScan [{'<root>': scan0}, collName]
+    BindBlock:
+        [scan0]
+            Source []
+
+-- OUTPUT:
+[4] nlj inner [] [s2] {((s2 == s4) ?: false)} 
+    left 
+        [1] project [s2 = getField(s1, "city")] 
+        [0] scan s1 none none none none none [] @"<collUUID>" true false 
+    right 
+        [3] project [s4 = getField(s3, "id")] 
+        [2] scan s3 none none none none none [] @"<collUUID>" true false 
+
+
+==== VARIATION: Nested loop join with equality predicate (Left join) ====
+-- INPUT:
+NestedLoopJoin [joinType: Left, {proj0}]
+|   |   BinaryOp [FillEmpty]
+|   |   |   Const [false]
+|   |   BinaryOp [Eq]
+|   |   |   Variable [proj1]
+|   |   Variable [proj0]
+|   Evaluation []
+|   |   BindBlock:
+|   |       [proj1]
+|   |           FunctionCall [getField]
+|   |           |   Const ["id"]
+|   |           Variable [scan1]
+|   PhysicalScan [{'<root>': scan1}, otherColl]
+|       BindBlock:
+|           [scan1]
+|               Source []
+Evaluation []
+|   BindBlock:
+|       [proj0]
+|           FunctionCall [getField]
+|           |   Const ["city"]
+|           Variable [scan0]
+PhysicalScan [{'<root>': scan0}, collName]
+    BindBlock:
+        [scan0]
+            Source []
+
+-- OUTPUT:
+[4] nlj left [] [s2] {((s2 == s4) ?: false)} 
+    left 
+        [1] project [s2 = getField(s1, "city")] 
+        [0] scan s1 none none none none none [] @"<collUUID>" true false 
+    right 
+        [3] project [s4 = getField(s3, "id")] 
+        [2] scan s3 none none none none none [] @"<collUUID>" true false 
+
-- 
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