fix(Ludicrous): Upserts on list type in Dgraph (#6754)

* Fix DGRAPH-2446: Dgraph missing upserts in ludicrous mode

* Add tests

* Address review comments

* Add a space

systest/ludicrous/upsert_test.go

@@ -0,0 +1,164 @@
+/*
+ * Copyright 2020 Dgraph Labs, Inc. and Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"sync"
+	"testing"
+
+	"github.com/dgraph-io/dgo/v200/protos/api"
+	"github.com/dgraph-io/dgraph/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+type Person struct {
+	Name  string `json:"name,omitempty"`
+	count int
+}
+
+type Data struct {
+	Name   string `json:"name,omitempty"`
+	Counts []int  `json:"count,omitempty"`
+}
+type ResponseData struct {
+	All []Data `json:"all,omitempty"`
+}
+
+func InitData(t *testing.T) {
+	dg, err := testutil.DgraphClient(testutil.SockAddr)
+	require.NoError(t, err)
+	testutil.DropAll(t, dg)
+	schema := `
+		name: string @index(exact) .
+		count: [int]  .
+	`
+
+	err = dg.Alter(context.Background(), &api.Operation{Schema: schema})
+	require.NoError(t, err)
+
+	p := Person{
+		Name:  "Alice",
+		count: 1,
+	}
+	pb, err := json.Marshal(p)
+	require.NoError(t, err)
+
+	mu := &api.Mutation{
+		SetJson:   pb,
+		CommitNow: true,
+	}
+	txn := dg.NewTxn()
+	ctx := context.Background()
+	defer txn.Discard(ctx)
+
+	_, err = txn.Mutate(ctx, mu)
+	require.NoError(t, err)
+}
+
+func TestConcurrentUpdate(t *testing.T) {
+	InitData(t)
+	ctx := context.Background()
+	dg, err := testutil.DgraphClient(testutil.SockAddr)
+	require.NoError(t, err)
+
+	count := 10
+	var wg sync.WaitGroup
+	wg.Add(count)
+	mutation := func(i int) {
+		defer wg.Done()
+		query := `query {
+			user as var(func: eq(name, "Alice"))
+			}`
+		mu := &api.Mutation{
+			SetNquads: []byte(fmt.Sprintf(`uid(user) <count> "%d" .`, i)),
+		}
+		req := &api.Request{
+			Query:     query,
+			Mutations: []*api.Mutation{mu},
+			CommitNow: true,
+		}
+		_, err := dg.NewTxn().Do(ctx, req)
+		require.NoError(t, err)
+	}
+	for i := 0; i < count; i++ {
+		go mutation(i)
+	}
+	wg.Wait()
+
+	q := `query all($a: string) {
+			all(func: eq(name, $a)) {
+			  name
+			  count
+			}
+		  }`
+
+	txn := dg.NewTxn()
+	res, err := txn.QueryWithVars(ctx, q, map[string]string{"$a": "Alice"})
+	require.NoError(t, err)
+	var dat ResponseData
+	err = json.Unmarshal(res.Json, &dat)
+	require.NoError(t, err)
+
+	require.Equal(t, len(dat.All[0].Counts), 10)
+}
+
+func TestSequentialUpdate(t *testing.T) {
+	InitData(t)
+	ctx := context.Background()
+	dg, err := testutil.DgraphClient(testutil.SockAddr)
+	require.NoError(t, err)
+
+	count := 10
+	mutation := func(i int) {
+		query := `query {
+			user as var(func: eq(name, "Alice"))
+			}`
+		mu := &api.Mutation{
+			SetNquads: []byte(fmt.Sprintf(`uid(user) <count> "%d" .`, i)),
+		}
+		req := &api.Request{
+			Query:     query,
+			Mutations: []*api.Mutation{mu},
+			CommitNow: true,
+		}
+		_, err := dg.NewTxn().Do(ctx, req)
+		require.NoError(t, err)
+
+	}
+	for i := 0; i < count; i++ {
+		mutation(i)
+	}
+
+	q := `query all($a: string) {
+			all(func: eq(name, $a)) {
+			  name
+			  count
+			}
+		  }`
+
+	txn := dg.NewTxn()
+	res, err := txn.QueryWithVars(ctx, q, map[string]string{"$a": "Alice"})
+	require.NoError(t, err)
+	var dat ResponseData
+	err = json.Unmarshal(res.Json, &dat)
+	require.NoError(t, err)
+
+	require.Equal(t, len(dat.All[0].Counts), 10)
+}

worker/draft.go

@@ -622,7 +622,8 @@ func (n *node) processApplyCh() {
 			psz := proposal.Size()
 			totalSize += int64(psz)
 
-			if x.WorkerConfig.LudicrousMode && proposal.Mutations != nil && proposal.Mutations.StartTs == 0 {
+			// In case of upserts the startTs would be > 0, so, no need to check startTs is 0
+			if x.WorkerConfig.LudicrousMode && proposal.Mutations != nil {
 				proposal.Mutations.StartTs = State.GetTimestamp(false)
 			}