Move tables with atomic transactions (#16676)

Signed-off-by: Manan Gupta <[email protected]>

doc/design-docs/AtomicTransactionsWithDisruptions.md

@@ -48,4 +48,14 @@ If it finds no prepared transaction of the table, it moves forward with the cut-
 In the Prepare code, we check the query rules before adding the transaction to the prepared list and re-check the rules before storing the transaction logs in the transaction redo table.
 Any transaction that went past the first check will fail the second check if the cutover proceeds.
 
-The check on both sides prevents either the cutover from proceeding or the transaction from being prepared.
+The check on both sides prevents either the cutover from proceeding or the transaction from being prepared.
+
+## MoveTables
+
+The only step of a `MoveTables` workflow that needs to synchronize with atomic transactions is `SwitchTraffic` for writes. As part of this step, we want to disallow writes to only the tables involved. We use `DeniedTables` in `ShardInfo` to accomplish this. After we update the topo server with the new `DeniedTables`, we make all the vttablets refresh their topo to ensure that they've registered the change.
+
+On vttablet, the `DeniedTables` are used to add query rules very similar to the ones in Online DDL. The only difference is that in Online DDL, we buffer the queries, but for `SwitchTraffic` we fail them altogether. Addition of these query rules, prevents any new atomic transactions from being prepared.
+
+Next, we try locking the tables to ensure no existing write is pending. This step blocks until all open prepared transactions have succeeded.
+
+After this step, `SwitchTraffic` can proceed without any issues, since we are guaranteed to reject any new atomic transactions until the `DeniedTables` has been reset, and having acquired the table lock, we know no write is currently in progress.

go/test/endtoend/cluster/move_tables.go

@@ -0,0 +1,94 @@
+/*
+Copyright 2024 The Vitess Authors.
+
+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 cluster
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+// MoveTablesWorkflow is used to store the information needed to run
+// MoveTables commands.
+type MoveTablesWorkflow struct {
+	t               *testing.T
+	clusterInstance *LocalProcessCluster
+	workflowName    string
+	targetKs        string
+	srcKs           string
+	tables          string
+}
+
+// NewMoveTables creates a new MoveTablesWorkflow.
+func NewMoveTables(t *testing.T, clusterInstance *LocalProcessCluster, workflowName, targetKs, srcKs, tables string) *MoveTablesWorkflow {
+	return &MoveTablesWorkflow{
+		t:               t,
+		clusterInstance: clusterInstance,
+		workflowName:    workflowName,
+		tables:          tables,
+		targetKs:        targetKs,
+		srcKs:           srcKs,
+	}
+}
+
+func (mtw *MoveTablesWorkflow) Create() (string, error) {
+	args := []string{"Create", "--source-keyspace=" + mtw.srcKs}
+	if mtw.tables != "" {
+		args = append(args, "--tables="+mtw.tables)
+	} else {
+		args = append(args, "--all-tables")
+	}
+	return mtw.exec(args...)
+}
+
+func (mtw *MoveTablesWorkflow) exec(args ...string) (string, error) {
+	args2 := []string{"MoveTables", "--workflow=" + mtw.workflowName, "--target-keyspace=" + mtw.targetKs}
+	args2 = append(args2, args...)
+	return mtw.clusterInstance.VtctldClientProcess.ExecuteCommandWithOutput(args2...)
+}
+
+func (mtw *MoveTablesWorkflow) SwitchReadsAndWrites() (string, error) {
+	return mtw.exec("SwitchTraffic")
+}
+
+func (mtw *MoveTablesWorkflow) ReverseReadsAndWrites() (string, error) {
+	return mtw.exec("ReverseTraffic")
+}
+
+func (mtw *MoveTablesWorkflow) Cancel() (string, error) {
+	return mtw.exec("Cancel")
+}
+
+func (mtw *MoveTablesWorkflow) Complete() (string, error) {
+	return mtw.exec("Complete")
+}
+
+func (mtw *MoveTablesWorkflow) Show() (string, error) {
+	return mtw.exec("Show")
+}
+
+func (mtw *MoveTablesWorkflow) WaitForVreplCatchup(timeToWait time.Duration) {
+	for _, ks := range mtw.clusterInstance.Keyspaces {
+		if ks.Name != mtw.targetKs {
+			continue
+		}
+		for _, shard := range ks.Shards {
+			vttablet := shard.PrimaryTablet().VttabletProcess
+			vttablet.WaitForVReplicationToCatchup(mtw.t, mtw.workflowName, fmt.Sprintf("vt_%s", vttablet.Keyspace), "", timeToWait)
+		}
+	}
+}

go/test/endtoend/cluster/vttablet_process.go

@@ -611,6 +611,7 @@ func (vttablet *VttabletProcess) getDBSystemValues(placeholder string, value str
 
 // WaitForVReplicationToCatchup waits for "workflow" to finish copying
 func (vttablet *VttabletProcess) WaitForVReplicationToCatchup(t testing.TB, workflow, database string, sidecarDBName string, duration time.Duration) {
+	t.Helper()
 	if sidecarDBName == "" {
 		sidecarDBName = sidecar.DefaultName
 	}

go/test/endtoend/onlineddl/vtgate_util.go

@@ -257,7 +257,8 @@ func CheckForceMigrationCutOver(t *testing.T, vtParams *mysql.ConnParams, shards
 
 // CheckMigrationStatus verifies that the migration indicated by given UUID has the given expected status
 func CheckMigrationStatus(t *testing.T, vtParams *mysql.ConnParams, shards []cluster.Shard, uuid string, expectStatuses ...schema.OnlineDDLStatus) bool {
-	query, err := sqlparser.ParseAndBind("show vitess_migrations like %a",
+	ksName := shards[0].PrimaryTablet().VttabletProcess.Keyspace
+	query, err := sqlparser.ParseAndBind(fmt.Sprintf("show vitess_migrations from %s like %%a", ksName),
 		sqltypes.StringBindVariable(uuid),
 	)
 	require.NoError(t, err)

go/test/endtoend/transaction/twopc/stress/fuzzer_test.go

@@ -29,6 +29,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/exp/rand"
 
@@ -102,12 +103,12 @@ func TestTwoPCFuzzTest(t *testing.T) {
 			timeForTesting: 5 * time.Second,
 		},
 		{
-			name:                  "Multiple Threads - Multiple Set - PRS, ERS, and MySQL & Vttablet restart, OnlineDDL disruptions",
-			threads:               15,
-			updateSets:            15,
+			name:                  "Multiple Threads - Multiple Set - PRS, ERS, and MySQL & Vttablet restart, OnlineDDL, MoveTables disruptions",
+			threads:               4,
+			updateSets:            4,
 			timeForTesting:        5 * time.Second,
-			clusterDisruptions:    []func(t *testing.T){prs, ers, mysqlRestarts, vttabletRestarts, onlineDDLFuzzer},
-			disruptionProbability: []int{5, 5, 5, 5, 5},
+			clusterDisruptions:    []func(t *testing.T){prs, ers, mysqlRestarts, vttabletRestarts, onlineDDLFuzzer, moveTablesFuzzer},
+			disruptionProbability: []int{5, 5, 5, 5, 5, 5},
 		},
 	}
 
@@ -443,7 +444,39 @@ func onlineDDLFuzzer(t *testing.T) {
 		return
 	}
 	fmt.Println("Running online DDL with uuid: ", output)
-	WaitForMigrationStatus(t, &vtParams, clusterInstance.Keyspaces[0].Shards, strings.TrimSpace(output), 2*time.Minute, schema.OnlineDDLStatusComplete, schema.OnlineDDLStatusFailed)
+	waitForMigrationStatus(t, &vtParams, clusterInstance.Keyspaces[0].Shards, strings.TrimSpace(output), 2*time.Minute, schema.OnlineDDLStatusComplete, schema.OnlineDDLStatusFailed)
+}
+
+var moveTablesCount int
+
+// moveTablesFuzzer runs a MoveTables workflow.
+func moveTablesFuzzer(t *testing.T) {
+	workflow := "TestTwoPCFuzzTest"
+	srcKeyspace := keyspaceName
+	targetKeyspace := unshardedKeyspaceName
+	if moveTablesCount%2 == 1 {
+		srcKeyspace = unshardedKeyspaceName
+		targetKeyspace = keyspaceName
+		// We apply the vschema again because previous move tables would have removed the entry for `twopc_fuzzer_update`.
+		err := clusterInstance.VtctldClientProcess.ApplyVSchema(keyspaceName, VSchema)
+		require.NoError(t, err)
+	}
+	log.Errorf("MoveTables from - %v to %v", srcKeyspace, targetKeyspace)
+	mtw := cluster.NewMoveTables(t, clusterInstance, workflow, targetKeyspace, srcKeyspace, "twopc_fuzzer_update")
+	// Initiate MoveTables for twopc_fuzzer_update.
+	output, err := mtw.Create()
+	if err != nil {
+		log.Errorf("error creating MoveTables - %v, output - %v", err, output)
+		return
+	}
+	moveTablesCount++
+	// Wait for vreplication to catchup. Should be very fast since we don't have a lot of rows.
+	mtw.WaitForVreplCatchup(1 * time.Minute)
+	// SwitchTraffic
+	output, err = mtw.SwitchReadsAndWrites()
+	assert.NoError(t, err, output)
+	output, err = mtw.Complete()
+	assert.NoError(t, err, output)
 }
 
 func mysqlRestarts(t *testing.T) {

go/test/endtoend/transaction/twopc/stress/main_test.go

@@ -32,13 +32,13 @@ import (
 )
 
 var (
-	clusterInstance   *cluster.LocalProcessCluster
-	vtParams          mysql.ConnParams
-	vtgateGrpcAddress string
-	keyspaceName      = "ks"
-	cell              = "zone1"
-	hostname          = "localhost"
-	sidecarDBName     = "vt_ks"
+	clusterInstance       *cluster.LocalProcessCluster
+	vtParams              mysql.ConnParams
+	vtgateGrpcAddress     string
+	keyspaceName          = "ks"
+	unshardedKeyspaceName = "uks"
+	cell                  = "zone1"
+	hostname              = "localhost"
 
 	//go:embed schema.sql
 	SchemaSQL string
@@ -79,18 +79,28 @@ func TestMain(m *testing.M) {
 			Name:             keyspaceName,
 			SchemaSQL:        SchemaSQL,
 			VSchema:          VSchema,
-			SidecarDBName:    sidecarDBName,
 			DurabilityPolicy: "semi_sync",
 		}
 		if err := clusterInstance.StartKeyspace(*keyspace, []string{"-40", "40-80", "80-"}, 2, false); err != nil {
 			return 1
 		}
 
+		// Start an unsharded keyspace
+		unshardedKeyspace := &cluster.Keyspace{
+			Name:             unshardedKeyspaceName,
+			SchemaSQL:        "",
+			VSchema:          "{}",
+			DurabilityPolicy: "semi_sync",
+		}
+		if err := clusterInstance.StartUnshardedKeyspace(*unshardedKeyspace, 2, false); err != nil {
+			return 1
+		}
+
 		// Start Vtgate
 		if err := clusterInstance.StartVtgate(); err != nil {
 			return 1
 		}
-		vtParams = clusterInstance.GetVTParams(keyspaceName)
+		vtParams = clusterInstance.GetVTParams("")
 		vtgateGrpcAddress = fmt.Sprintf("%s:%d", clusterInstance.Hostname, clusterInstance.VtgateGrpcPort)
 
 		return m.Run()

go/test/endtoend/transaction/twopc/stress/stress_test.go

@@ -48,6 +48,7 @@ func TestDisruptions(t *testing.T) {
 		disruptionName  string
 		commitDelayTime string
 		disruption      func(t *testing.T) error
+		resetFunc       func(t *testing.T)
 	}{
 		{
 			disruptionName:  "No Disruption",
@@ -76,6 +77,17 @@ func TestDisruptions(t *testing.T) {
 			commitDelayTime: "20",
 			disruption:      onlineDDL,
 		},
+		{
+			disruptionName:  "MoveTables - Complete",
+			commitDelayTime: "10",
+			disruption:      moveTablesComplete,
+			resetFunc:       moveTablesReset,
+		},
+		{
+			disruptionName:  "MoveTables - Cancel",
+			commitDelayTime: "10",
+			disruption:      moveTablesCancel,
+		},
 		{
 			disruptionName:  "EmergencyReparentShard",
 			commitDelayTime: "5",
@@ -136,6 +148,10 @@ func TestDisruptions(t *testing.T) {
 			waitForResults(t, "select id, col from twopc_t1 where col = 4 order by id", `[[INT64(4) INT64(4)] [INT64(6) INT64(4)] [INT64(9) INT64(4)]]`, 30*time.Second)
 			writeCancel()
 			writerWg.Wait()
+
+			if tt.resetFunc != nil {
+				tt.resetFunc(t)
+			}
 		})
 	}
 }
@@ -239,6 +255,61 @@ func mysqlRestartShard3(t *testing.T) error {
 	return syscallutil.Kill(pid, syscall.SIGKILL)
 }
 
+// moveTablesCancel runs a move tables command that we cancel in the end.
+func moveTablesCancel(t *testing.T) error {
+	workflow := "TestDisruptions"
+	mtw := cluster.NewMoveTables(t, clusterInstance, workflow, unshardedKeyspaceName, keyspaceName, "twopc_t1")
+	// Initiate MoveTables for twopc_t1.
+	output, err := mtw.Create()
+	require.NoError(t, err, output)
+	// Wait for vreplication to catchup. Should be very fast since we don't have a lot of rows.
+	mtw.WaitForVreplCatchup(10 * time.Second)
+	// SwitchTraffic
+	output, err = mtw.SwitchReadsAndWrites()
+	require.NoError(t, err, output)
+	output, err = mtw.ReverseReadsAndWrites()
+	require.NoError(t, err, output)
+	output, err = mtw.Cancel()
+	require.NoError(t, err, output)
+	return nil
+}
+
+// moveTablesComplete runs a move tables command that we complete in the end.
+func moveTablesComplete(t *testing.T) error {
+	workflow := "TestDisruptions"
+	mtw := cluster.NewMoveTables(t, clusterInstance, workflow, unshardedKeyspaceName, keyspaceName, "twopc_t1")
+	// Initiate MoveTables for twopc_t1.
+	output, err := mtw.Create()
+	require.NoError(t, err, output)
+	// Wait for vreplication to catchup. Should be very fast since we don't have a lot of rows.
+	mtw.WaitForVreplCatchup(10 * time.Second)
+	// SwitchTraffic
+	output, err = mtw.SwitchReadsAndWrites()
+	require.NoError(t, err, output)
+	output, err = mtw.Complete()
+	require.NoError(t, err, output)
+	return nil
+}
+
+// moveTablesReset moves the table back from the unsharded keyspace to sharded
+func moveTablesReset(t *testing.T) {
+	// We apply the vschema again because previous move tables would have removed the entry for `twopc_t1`.
+	err := clusterInstance.VtctldClientProcess.ApplyVSchema(keyspaceName, VSchema)
+	require.NoError(t, err)
+	workflow := "TestDisruptions"
+	mtw := cluster.NewMoveTables(t, clusterInstance, workflow, keyspaceName, unshardedKeyspaceName, "twopc_t1")
+	// Initiate MoveTables for twopc_t1.
+	output, err := mtw.Create()
+	require.NoError(t, err, output)
+	// Wait for vreplication to catchup. Should be very fast since we don't have a lot of rows.
+	mtw.WaitForVreplCatchup(10 * time.Second)
+	// SwitchTraffic
+	output, err = mtw.SwitchReadsAndWrites()
+	require.NoError(t, err, output)
+	output, err = mtw.Complete()
+	require.NoError(t, err, output)
+}
+
 var orderedDDL = []string{
 	"alter table twopc_t1 add column extra_col1 varchar(20)",
 	"alter table twopc_t1 add column extra_col2 varchar(20)",
@@ -256,18 +327,18 @@ func onlineDDL(t *testing.T) error {
 	require.NoError(t, err)
 	count++
 	fmt.Println("uuid: ", output)
-	status := WaitForMigrationStatus(t, &vtParams, clusterInstance.Keyspaces[0].Shards, strings.TrimSpace(output), 2*time.Minute, schema.OnlineDDLStatusComplete, schema.OnlineDDLStatusFailed)
+	status := waitForMigrationStatus(t, &vtParams, clusterInstance.Keyspaces[0].Shards, strings.TrimSpace(output), 2*time.Minute, schema.OnlineDDLStatusComplete, schema.OnlineDDLStatusFailed)
 	onlineddl.CheckMigrationStatus(t, &vtParams, clusterInstance.Keyspaces[0].Shards, strings.TrimSpace(output), status)
 	require.Equal(t, schema.OnlineDDLStatusComplete, status)
 	return nil
 }
 
-func WaitForMigrationStatus(t *testing.T, vtParams *mysql.ConnParams, shards []cluster.Shard, uuid string, timeout time.Duration, expectStatuses ...schema.OnlineDDLStatus) schema.OnlineDDLStatus {
+func waitForMigrationStatus(t *testing.T, vtParams *mysql.ConnParams, shards []cluster.Shard, uuid string, timeout time.Duration, expectStatuses ...schema.OnlineDDLStatus) schema.OnlineDDLStatus {
 	shardNames := map[string]bool{}
 	for _, shard := range shards {
 		shardNames[shard.Name] = true
 	}
-	query := fmt.Sprintf("show vitess_migrations like '%s'", uuid)
+	query := fmt.Sprintf("show vitess_migrations from %s like '%s'", keyspaceName, uuid)
 
 	statusesMap := map[string]bool{}
 	for _, status := range expectStatuses {
@@ -280,6 +351,11 @@ func WaitForMigrationStatus(t *testing.T, vtParams *mysql.ConnParams, shards []c
 
 	lastKnownStatus := ""
 	for {
+		select {
+		case <-ctx.Done():
+			return schema.OnlineDDLStatus(lastKnownStatus)
+		case <-ticker.C:
+		}
 		countMatchedShards := 0
 		conn, err := mysql.Connect(ctx, vtParams)
 		if err != nil {
@@ -304,10 +380,5 @@ func WaitForMigrationStatus(t *testing.T, vtParams *mysql.ConnParams, shards []c
 		if countMatchedShards == len(shards) {
 			return schema.OnlineDDLStatus(lastKnownStatus)
 		}
-		select {
-		case <-ctx.Done():
-			return schema.OnlineDDLStatus(lastKnownStatus)
-		case <-ticker.C:
-		}
 	}
 }