fix equality check in buildSingleLookupPlan()

enginetest/join_planning_tests.go

@@ -1788,6 +1788,34 @@ join uv d on d.u = c.x`,
 			},
 		},
 	},
+	{
+		name: "single look up plan does not drop complex equality filters",
+		setup: []string{
+			"create table t1 (i int primary key);",
+			"create table t2 (j int);",
+			"create table t3 (k int);",
+			"insert into t1 values (1), (2);",
+			"insert into t2 values (1), (2);",
+			"insert into t3 values (3);",
+		},
+		tests: []JoinPlanTest{
+			{
+				q:     "select * from t1 cross join t2 join (select * from t3) v3 on v3.k = t2.j;",
+				types: []plan.JoinType{plan.JoinTypeHash, plan.JoinTypeCross},
+				exp:   []sql.Row{},
+			},
+			{
+				q:     "select * from t1 cross join t2 join (select * from t3) v3 on v3.k >= t2.j order by i, j, k;",
+				types: []plan.JoinType{plan.JoinTypeInner, plan.JoinTypeCross},
+				exp: []sql.Row{
+					{1, 1, 3},
+					{1, 2, 3},
+					{2, 1, 3},
+					{2, 2, 3},
+				},
+			},
+		},
+	},
 }
 
 func TestJoinPlanning(t *testing.T, harness Harness) {

sql/memo/join_order_builder.go

@@ -285,7 +285,7 @@ func (j *joinOrderBuilder) buildSingleLookupPlan() bool {
 			}
 			filter := edge.filters[0]
 			_, tables, _ := getExprScalarProps(filter)
-			if tables.Len() != 2 {
+			if tables.Len() != 2 || !isSimpleEquality(filter) {
 				// We have encountered a filter condition more complicated than a simple equality check.
 				// We probably can't optimize this, so bail out.
 				return false
@@ -319,7 +319,6 @@ func (j *joinOrderBuilder) buildSingleLookupPlan() bool {
 			for idx, ok := remainingVertexes.next(0); ok; idx, ok = remainingVertexes.next(idx + 1) {
 				nextVertex := newBitSet(idx)
 				j.addJoin(plan.JoinTypeCross, currentlyJoinedVertexes, nextVertex, nil, nil, false)
-
 				currentlyJoinedVertexes = currentlyJoinedVertexes.union(nextVertex)
 			}
 			return false

sql/memo/rel_props.go

@@ -538,6 +538,21 @@ func getExprScalarProps(e sql.Expression) (sql.ColSet, sql.FastIntSet, bool) {
 	return cols, tables, nullRej
 }
 
+func isSimpleEquality(expr sql.Expression) bool {
+	hasOnlyEquals := true
+	transform.InspectExpr(expr, func(e sql.Expression) bool {
+		switch e.(type) {
+		case *expression.GetField:
+		case *expression.Equals, *expression.NullSafeEquals:
+		default:
+			hasOnlyEquals = false
+			return true
+		}
+		return false
+	})
+	return hasOnlyEquals
+}
+
 // allTableCols returns the full schema of a table ignoring
 // declared projections.
 func allTableCols(rel SourceRel) sql.Schema {