[rowexec] full outer join rightIter exhaust (#2814)

Author: max-hoffman

enginetest/queries/script_queries.go

@@ -114,6 +114,35 @@ type ScriptTestAssertion struct {
 // Unlike other engine tests, ScriptTests must be self-contained. No other tables are created outside the definition of
 // the tests.
 var ScriptTests = []ScriptTest{
+	{
+		Name: "outer join finish unmatched right side",
+		SetUpScript: []string{
+			`
+CREATE TABLE teams (
+  team VARCHAR(100),
+  namespace VARCHAR(100)
+);`,
+			"INSERT INTO teams(team, namespace) VALUES ('sam', 'sam1');",
+			"INSERT INTO teams(team, namespace) VALUES ('sam', 'sam2');",
+			"INSERT INTO teams(team, namespace) VALUES ('janos', 'janos1');",
+			`CREATE TABLE traces (
+  namespace VARCHAR(100),
+  value INT
+);`,
+			"INSERT INTO traces(namespace, value) VALUES ('janos1', '400');",
+			"INSERT INTO traces(namespace, value) VALUES ('0', '500');",
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query:    "SELECT  team,  sum(value) FROM traces FULL OUTER JOIN teams ON teams.namespace = traces.namespace GROUP BY team;",
+				Expected: []sql.Row{{"sam", nil}, {"janos", float64(400)}, {nil, float64(500)}},
+			},
+			{
+				Query:    "SELECT  team,  sum(value) FROM teams FULL OUTER JOIN traces ON teams.namespace = traces.namespace GROUP BY team;",
+				Expected: []sql.Row{{"sam", nil}, {"janos", float64(400)}, {nil, float64(500)}},
+			},
+		},
+	},
 	{
 		Name: "keyless reverse index",
 		SetUpScript: []string{

sql/rowexec/join_iters.go

@@ -404,6 +404,8 @@ func newFullJoinIter(ctx *sql.Context, b sql.NodeExecBuilder, j *plan.JoinNode,
 		rowSize:   len(row) + len(j.Left().Schema()) + len(j.Right().Schema()),
 		seenLeft:  make(map[uint64]struct{}),
 		seenRight: make(map[uint64]struct{}),
+		leftLen:   len(j.Left().Schema()),
+		rightLen:  len(j.Right().Schema()),
 		b:         b,
 	}, nil
 }
@@ -422,6 +424,8 @@ type fullJoinIter struct {
 	leftRow   sql.Row
 	scopeLen  int
 	rowSize   int
+	leftLen   int
+	rightLen  int
 
 	leftDone  bool
 	seenLeft  map[uint64]struct{}
@@ -439,6 +443,7 @@ func (i *fullJoinIter) Next(ctx *sql.Context) (sql.Row, error) {
 				i.leftDone = true
 				i.l = nil
 				i.r = nil
+				continue
 			}
 			if err != nil {
 				return nil, err
@@ -463,7 +468,7 @@ func (i *fullJoinIter) Next(ctx *sql.Context) (sql.Row, error) {
 			}
 			if _, ok := i.seenLeft[key]; !ok {
 				// (left, null) only if we haven't matched left
-				ret := i.buildRow(i.leftRow, nil)
+				ret := i.buildRow(i.leftRow, make(sql.Row, i.rightLen))
 				i.r = nil
 				i.leftRow = nil
 				return i.removeParentRow(ret), nil
@@ -520,7 +525,7 @@ func (i *fullJoinIter) Next(ctx *sql.Context) (sql.Row, error) {
 			continue
 		}
 		// (null, right) only if we haven't matched right
-		ret := i.buildRow(nil, rightRow)
+		ret := i.buildRow(make(sql.Row, i.leftLen), rightRow)
 		return i.removeParentRow(ret), nil
 	}
 }