BREAKING: fix json marshal unmarshal for namespace > 127 (#7810)

We used to store predicate as <namespace>|<attribute>
(pipe | signifies concatenation). We store this as a string.
<namespace> is 8 bytes uint64, which when marshaled to JSON bytes
mess up the predicate. This is because for the namespace greater
than 127, the UTF-8 encoding might take up several bytes
(also if the mapping does not exist, then it replaces it with
some other rune).

This affects three identified places in Dgraph:
  * Live loader
  * Backup and List Backup
  * Http clients and Ratel

Fix is to have a UTF-8 string when dealing with JSON. A better idea
is to use UTF-8 string even for internal operations. Only when we
read/write to badger we convert it into the format of the byte.
New Format: <anmespace>-<attribute> (- is the hyphen literal)

dgraph/cmd/alpha/http_test.go

@@ -428,7 +428,7 @@ func TestTransactionBasic(t *testing.T) {
 	require.Equal(t, 2, len(mr.preds))
 	var parsedPreds []string
 	for _, pred := range mr.preds {
-		p := strings.Split(pred, "-")[1]
+		p := strings.SplitN(pred, "-", 2)[1]
 		parsedPreds = append(parsedPreds, x.ParseAttr(p))
 	}
 	sort.Strings(parsedPreds)

dgraph/cmd/alpha/upsert_test.go

@@ -39,7 +39,7 @@ type QueryResult struct {
 
 func splitPreds(ps []string) []string {
 	for i, p := range ps {
-		ps[i] = x.ParseAttr(strings.Split(p, "-")[1])
+		ps[i] = x.ParseAttr(strings.SplitN(p, "-", 2)[1])
 	}
 
 	return ps

dgraph/cmd/zero/oracle.go

@@ -370,15 +370,15 @@ func (s *Server) commit(ctx context.Context, src *api.TxnContext) error {
 	checkPreds := func() error {
 		// Check if any of these tablets is being moved. If so, abort the transaction.
 		for _, pkey := range src.Preds {
-			splits := strings.Split(pkey, "-")
+			splits := strings.SplitN(pkey, "-", 2)
 			if len(splits) < 2 {
 				return errors.Errorf("Unable to find group id in %s", pkey)
 			}
 			gid, err := strconv.Atoi(splits[0])
 			if err != nil {
 				return errors.Wrapf(err, "unable to parse group id from %s", pkey)
 			}
-			pred := strings.Join(splits[1:], "-")
+			pred := splits[1]
 			tablet := s.ServingTablet(pred)
 			if tablet == nil {
 				return errors.Errorf("Tablet for %s is nil", pred)

edgraph/server.go

@@ -1061,16 +1061,7 @@ func filterTablets(ctx context.Context, ms *pb.MembershipState) error {
 		return errors.Errorf("Namespace not found in JWT.")
 	}
 	if namespace == x.GalaxyNamespace {
-		// For galaxy namespace, we don't want to filter out the predicates. We only format the
-		// namespace to human readable form.
-		for _, group := range ms.Groups {
-			tablets := make(map[string]*pb.Tablet)
-			for tabletName, tablet := range group.Tablets {
-				tablet.Predicate = x.FormatNsAttr(tablet.Predicate)
-				tablets[x.FormatNsAttr(tabletName)] = tablet
-			}
-			group.Tablets = tablets
-		}
+		// For galaxy namespace, we don't want to filter out the predicates.
 		return nil
 	}
 	for _, group := range ms.GetGroups() {

posting/index.go

@@ -592,16 +592,15 @@ func (r *rebuilder) Run(ctx context.Context) error {
 
 	glog.V(1).Infof(
 		"Rebuilding index for predicate %s: Starting process. StartTs=%d. Prefix=\n%s\n",
-		x.FormatNsAttr(r.attr), r.startTs, hex.Dump(r.prefix))
+		r.attr, r.startTs, hex.Dump(r.prefix))
 
 	// Counter is used here to ensure that all keys are committed at different timestamp.
 	// We set it to 1 in case there are no keys found and NewStreamAt is called with ts=0.
 	var counter uint64 = 1
 
 	tmpWriter := tmpDB.NewManagedWriteBatch()
 	stream := pstore.NewStreamAt(r.startTs)
-	stream.LogPrefix = fmt.Sprintf("Rebuilding index for predicate %s (1/2):",
-		x.FormatNsAttr(r.attr))
+	stream.LogPrefix = fmt.Sprintf("Rebuilding index for predicate %s (1/2):", r.attr)
 	stream.Prefix = r.prefix
 	stream.KeyToList = func(key []byte, itr *badger.Iterator) (*bpb.KVList, error) {
 		// We should return quickly if the context is no longer valid.
@@ -663,21 +662,19 @@ func (r *rebuilder) Run(ctx context.Context) error {
 		return err
 	}
 	glog.V(1).Infof("Rebuilding index for predicate %s: building temp index took: %v\n",
-		x.FormatNsAttr(r.attr), time.Since(start))
+		r.attr, time.Since(start))
 
 	// Now we write all the created posting lists to disk.
-	glog.V(1).Infof("Rebuilding index for predicate %s: writing index to badger",
-		x.FormatNsAttr(r.attr))
+	glog.V(1).Infof("Rebuilding index for predicate %s: writing index to badger", r.attr)
 	start = time.Now()
 	defer func() {
 		glog.V(1).Infof("Rebuilding index for predicate %s: writing index took: %v\n",
-			x.FormatNsAttr(r.attr), time.Since(start))
+			r.attr, time.Since(start))
 	}()
 
 	writer := pstore.NewManagedWriteBatch()
 	tmpStream := tmpDB.NewStreamAt(counter)
-	tmpStream.LogPrefix = fmt.Sprintf("Rebuilding index for predicate %s (2/2):",
-		x.FormatNsAttr(r.attr))
+	tmpStream.LogPrefix = fmt.Sprintf("Rebuilding index for predicate %s (2/2):", r.attr)
 	tmpStream.KeyToList = func(key []byte, itr *badger.Iterator) (*bpb.KVList, error) {
 		l, err := ReadPostingList(key, itr)
 		if err != nil {
@@ -720,8 +717,7 @@ func (r *rebuilder) Run(ctx context.Context) error {
 	if err := tmpStream.Orchestrate(ctx); err != nil {
 		return err
 	}
-	glog.V(1).Infof("Rebuilding index for predicate %s: Flushing all writes.\n",
-		x.FormatNsAttr(r.attr))
+	glog.V(1).Infof("Rebuilding index for predicate %s: Flushing all writes.\n", r.attr)
 	return writer.Flush()
 }
 

posting/list_test.go

@@ -559,7 +559,7 @@ func TestAddMutation_mrjn2(t *testing.T) {
 }
 
 func TestAddMutation_gru(t *testing.T) {
-	key := x.DataKey("question.tag", 0x01)
+	key := x.DataKey(x.GalaxyAttr("question.tag"), 0x01)
 	ol, err := getNew(key, ps, math.MaxUint64)
 	require.NoError(t, err)
 
@@ -592,7 +592,7 @@ func TestAddMutation_gru(t *testing.T) {
 }
 
 func TestAddMutation_gru2(t *testing.T) {
-	key := x.DataKey("question.tag", 0x100)
+	key := x.DataKey(x.GalaxyAttr("question.tag"), 0x100)
 	ol, err := getNew(key, ps, math.MaxUint64)
 	require.NoError(t, err)
 
@@ -639,7 +639,7 @@ func TestAddMutation_gru2(t *testing.T) {
 func TestAddAndDelMutation(t *testing.T) {
 	// Ensure each test uses unique key since we don't clear the postings
 	// after each test
-	key := x.DataKey("dummy_key", 0x927)
+	key := x.DataKey(x.GalaxyAttr("dummy_key"), 0x927)
 	ol, err := getNew(key, ps, math.MaxUint64)
 	require.NoError(t, err)
 
@@ -878,7 +878,7 @@ func createMultiPartList(t *testing.T, size int, addFacet bool) (*List, int) {
 	defer setMaxListSize(maxListSize)
 	maxListSize = 5000
 
-	key := x.DataKey(uuid.New().String(), 1331)
+	key := x.DataKey(x.GalaxyAttr(uuid.New().String()), 1331)
 	ol, err := getNew(key, ps, math.MaxUint64)
 	require.NoError(t, err)
 	commits := 0
@@ -926,7 +926,7 @@ func createAndDeleteMultiPartList(t *testing.T, size int) (*List, int) {
 	defer setMaxListSize(maxListSize)
 	maxListSize = 10000
 
-	key := x.DataKey(uuid.New().String(), 1331)
+	key := x.DataKey(x.GalaxyAttr(uuid.New().String()), 1331)
 	ol, err := getNew(key, ps, math.MaxUint64)
 	require.NoError(t, err)
 	commits := 0
@@ -1087,7 +1087,7 @@ func TestBinSplit(t *testing.T) {
 		defer func() {
 			maxListSize = originalListSize
 		}()
-		key := x.DataKey(uuid.New().String(), 1331)
+		key := x.DataKey(x.GalaxyAttr(uuid.New().String()), 1331)
 		ol, err := getNew(key, ps, math.MaxUint64)
 		require.NoError(t, err)
 		for i := 1; i <= size; i++ {
@@ -1268,7 +1268,7 @@ func TestMultiPartListDeleteAndAdd(t *testing.T) {
 	maxListSize = 5000
 
 	// Add entries to the maps.
-	key := x.DataKey(uuid.New().String(), 1331)
+	key := x.DataKey(x.GalaxyAttr(uuid.New().String()), 1331)
 	ol, err := getNew(key, ps, math.MaxUint64)
 	require.NoError(t, err)
 	for i := 1; i <= size; i++ {
@@ -1407,7 +1407,7 @@ func TestRecursiveSplits(t *testing.T) {
 
 	// Create a list that should be split recursively.
 	size := int(1e5)
-	key := x.DataKey(uuid.New().String(), 1331)
+	key := x.DataKey(x.GalaxyAttr(uuid.New().String()), 1331)
 	ol, err := getNew(key, ps, math.MaxUint64)
 	require.NoError(t, err)
 	commits := 0

worker/groups.go

@@ -487,7 +487,7 @@ func (g *groupi) sendTablet(tablet *pb.Tablet) (*pb.Tablet, error) {
 	}
 
 	if out.GroupId == groups().groupId() {
-		glog.Infof("Serving tablet for: %v\n", x.FormatNsAttr(tablet.GetPredicate()))
+		glog.Infof("Serving tablet for: %v\n", tablet.GetPredicate())
 	}
 	return out, nil
 }
@@ -534,7 +534,7 @@ func (g *groupi) Inform(preds []string) ([]*pb.Tablet, error) {
 		}
 
 		if t.GroupId == groups().groupId() {
-			glog.Infof("Serving tablet for: %v\n", x.FormatNsAttr(t.GetPredicate()))
+			glog.Infof("Serving tablet for: %v\n", t.GetPredicate())
 		}
 	}
 	g.Unlock()