lightning: add back table empty check and add a switch config

br/pkg/lightning/config/config.go

@@ -527,6 +527,7 @@ type TikvImporter struct {
 	DiskQuota           ByteSize                     `toml:"disk-quota" json:"disk-quota"`
 	RangeConcurrency    int                          `toml:"range-concurrency" json:"range-concurrency"`
 	DuplicateResolution DuplicateResolutionAlgorithm `toml:"duplicate-resolution" json:"duplicate-resolution"`
+	IncrementalImport   bool                         `toml:"incremental-import" json:"incremental-import"`
 
 	EngineMemCacheSize      ByteSize `toml:"engine-mem-cache-size" json:"engine-mem-cache-size"`
 	LocalWriterMemCacheSize ByteSize `toml:"local-writer-mem-cache-size" json:"local-writer-mem-cache-size"`

br/pkg/lightning/restore/check_info.go

@@ -17,17 +17,23 @@ package restore
 import (
 	"bytes"
 	"context"
+	"database/sql"
 	"fmt"
 	"io"
 	"path/filepath"
 	"reflect"
 	"sort"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/docker/go-units"
 	"github.com/pingcap/errors"
 	"github.com/pingcap/failpoint"
+	"go.uber.org/zap"
+	"golang.org/x/sync/errgroup"
+	"modernc.org/mathutil"
+
 	"github.com/pingcap/kvproto/pkg/metapb"
 	"github.com/pingcap/tidb/br/pkg/lightning/backend"
 	"github.com/pingcap/tidb/br/pkg/lightning/backend/kv"
@@ -38,16 +44,14 @@ import (
 	"github.com/pingcap/tidb/br/pkg/lightning/mydump"
 	"github.com/pingcap/tidb/br/pkg/lightning/verification"
 	"github.com/pingcap/tidb/br/pkg/storage"
+	"github.com/pingcap/tidb/br/pkg/utils"
 	"github.com/pingcap/tidb/parser/model"
 	"github.com/pingcap/tidb/parser/mysql"
 	"github.com/pingcap/tidb/table"
 	"github.com/pingcap/tidb/table/tables"
 	"github.com/pingcap/tidb/types"
 	"github.com/tikv/pd/server/api"
 	pdconfig "github.com/tikv/pd/server/config"
-
-	"go.uber.org/zap"
-	"modernc.org/mathutil"
 )
 
 const (
@@ -1053,3 +1057,84 @@ outloop:
 	log.L().Info("Sample source data", zap.String("table", tableMeta.Name), zap.Float64("IndexRatio", tableMeta.IndexRatio), zap.Bool("IsSourceOrder", tableMeta.IsRowOrdered))
 	return nil
 }
+
+func (rc *Controller) checkTableEmpty(ctx context.Context) error {
+	if rc.cfg.TikvImporter.Backend == config.BackendTiDB || rc.cfg.TikvImporter.IncrementalImport {
+		return nil
+	}
+	db, _ := rc.tidbGlue.GetDB()
+
+	tableCount := 0
+	for _, db := range rc.dbMetas {
+		tableCount += len(db.Tables)
+	}
+
+	var lock sync.Mutex
+	tableNames := make([]string, 0)
+	concurrency := utils.MinInt(tableCount, rc.cfg.App.RegionConcurrency)
+	ch := make(chan string, concurrency)
+	eg, gCtx := errgroup.WithContext(ctx)
+	for i := 0; i < concurrency; i++ {
+		eg.Go(func() error {
+			for tblName := range ch {
+				// skip tables that have checkpoint
+				if rc.cfg.Checkpoint.Enable {
+					_, err := rc.checkpointsDB.Get(gCtx, tblName)
+					switch {
+					case err == nil:
+						continue
+					case errors.IsNotFound(err):
+					default:
+						return errors.Trace(err)
+					}
+				}
+
+				hasData, err1 := tableContainsData(gCtx, db, tblName)
+				if err1 != nil {
+					return err1
+				}
+				if hasData {
+					lock.Lock()
+					tableNames = append(tableNames, tblName)
+					lock.Unlock()
+				}
+			}
+			return nil
+		})
+	}
+	for _, db := range rc.dbMetas {
+		for _, tbl := range db.Tables {
+			ch <- common.UniqueTable(tbl.DB, tbl.Name)
+		}
+	}
+	close(ch)
+	if err := eg.Wait(); err != nil {
+		if common.IsContextCanceledError(err) {
+			return nil
+		}
+		return errors.Trace(err)
+	}
+
+	if len(tableNames) > 0 {
+		// sort the failed names
+		sort.Strings(tableNames)
+		msg := fmt.Sprintf("table(s) [%s] are not empty", strings.Join(tableNames, ", "))
+		rc.checkTemplate.Collect(Critical, false, msg)
+	}
+	return nil
+}
+
+func tableContainsData(ctx context.Context, db utils.QueryExecutor, tableName string) (bool, error) {
+	query := "select 1 from " + tableName + " limit 1"
+	var dump int
+	err := db.QueryRowContext(ctx, query).Scan(&dump)
+
+	switch {
+	case err == sql.ErrNoRows:
+		return false, nil
+	case err != nil:
+		return false, errors.Trace(err)
+	default:
+		return true, nil
+	}
+}

br/pkg/lightning/restore/check_info_test.go

@@ -16,15 +16,18 @@ package restore
 
 import (
 	"context"
+	"database/sql"
 	"fmt"
 	"os"
 	"path/filepath"
 
+	"github.com/DATA-DOG/go-sqlmock"
 	. "github.com/pingcap/check"
 	"github.com/pingcap/failpoint"
 
 	"github.com/pingcap/tidb/br/pkg/lightning/checkpoints"
 	"github.com/pingcap/tidb/br/pkg/lightning/config"
+	"github.com/pingcap/tidb/br/pkg/lightning/glue"
 	"github.com/pingcap/tidb/br/pkg/lightning/mydump"
 	"github.com/pingcap/tidb/br/pkg/lightning/worker"
 	"github.com/pingcap/tidb/br/pkg/storage"
@@ -404,6 +407,142 @@ func (s *checkInfoSuite) TestCheckCSVHeader(c *C) {
 	}
 }
 
+func (s *checkInfoSuite) TestCheckTableEmpty(c *C) {
+	dir := c.MkDir()
+	cfg := config.NewConfig()
+	cfg.Checkpoint.Enable = false
+	dbMetas := []*mydump.MDDatabaseMeta{
+		{
+			Name: "test1",
+			Tables: []*mydump.MDTableMeta{
+				{
+					DB:   "test1",
+					Name: "tbl1",
+				},
+				{
+					DB:   "test1",
+					Name: "tbl2",
+				},
+			},
+		},
+		{
+			Name: "test2",
+			Tables: []*mydump.MDTableMeta{
+				{
+					DB:   "test2",
+					Name: "tbl1",
+				},
+			},
+		},
+	}
+
+	rc := &Controller{
+		cfg:           cfg,
+		dbMetas:       dbMetas,
+		checkpointsDB: checkpoints.NewNullCheckpointsDB(),
+	}
+
+	ctx := context.Background()
+
+	// test tidb will do nothing
+	rc.cfg.TikvImporter.Backend = config.BackendTiDB
+	err := rc.checkTableEmpty(ctx)
+	c.Assert(err, IsNil)
+
+	// test incremental mode
+	rc.cfg.TikvImporter.Backend = config.BackendLocal
+	rc.cfg.TikvImporter.IncrementalImport = true
+	err = rc.checkTableEmpty(ctx)
+	c.Assert(err, IsNil)
+
+	rc.cfg.TikvImporter.IncrementalImport = false
+	db, mock, err := sqlmock.New()
+	c.Assert(err, IsNil)
+	mock.MatchExpectationsInOrder(false)
+	rc.tidbGlue = glue.NewExternalTiDBGlue(db, mysql.ModeNone)
+	mock.ExpectQuery("select 1 from `test1`.`tbl1` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).RowError(0, sql.ErrNoRows))
+	mock.ExpectQuery("select 1 from `test1`.`tbl2` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).RowError(0, sql.ErrNoRows))
+	mock.ExpectQuery("select 1 from `test2`.`tbl1` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).RowError(0, sql.ErrNoRows))
+	// not error, need not to init check template
+	err = rc.checkTableEmpty(ctx)
+	c.Assert(err, IsNil)
+	c.Assert(mock.ExpectationsWereMet(), IsNil)
+
+	// single table contains data
+	db, mock, err = sqlmock.New()
+	c.Assert(err, IsNil)
+	rc.tidbGlue = glue.NewExternalTiDBGlue(db, mysql.ModeNone)
+	mock.MatchExpectationsInOrder(false)
+	mock.ExpectQuery("select 1 from `test1`.`tbl1` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).RowError(0, sql.ErrNoRows))
+	mock.ExpectQuery("select 1 from `test1`.`tbl2` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).RowError(0, sql.ErrNoRows))
+	mock.ExpectQuery("select 1 from `test2`.`tbl1` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).AddRow(1))
+	rc.checkTemplate = NewSimpleTemplate()
+	err = rc.checkTableEmpty(ctx)
+	c.Assert(err, IsNil)
+	c.Assert(mock.ExpectationsWereMet(), IsNil)
+	tmpl := rc.checkTemplate.(*SimpleTemplate)
+	c.Assert(len(tmpl.criticalMsgs), Equals, 1)
+	c.Assert(tmpl.criticalMsgs[0], Matches, "table\\(s\\) \\[`test2`.`tbl1`\\] are not empty")
+
+	// multi tables contains data
+	db, mock, err = sqlmock.New()
+	c.Assert(err, IsNil)
+	rc.tidbGlue = glue.NewExternalTiDBGlue(db, mysql.ModeNone)
+	mock.MatchExpectationsInOrder(false)
+	mock.ExpectQuery("select 1 from `test1`.`tbl1` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).AddRow(1))
+	mock.ExpectQuery("select 1 from `test1`.`tbl2` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).RowError(0, sql.ErrNoRows))
+	mock.ExpectQuery("select 1 from `test2`.`tbl1` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).AddRow(1))
+	rc.checkTemplate = NewSimpleTemplate()
+	err = rc.checkTableEmpty(ctx)
+	c.Assert(err, IsNil)
+	c.Assert(mock.ExpectationsWereMet(), IsNil)
+	tmpl = rc.checkTemplate.(*SimpleTemplate)
+	c.Assert(len(tmpl.criticalMsgs), Equals, 1)
+	c.Assert(tmpl.criticalMsgs[0], Matches, "table\\(s\\) \\[`test1`.`tbl1`, `test2`.`tbl1`\\] are not empty")
+
+	// init checkpoint with only two of the three tables
+	dbInfos := map[string]*checkpoints.TidbDBInfo{
+		"test1": {
+			Name: "test1",
+			Tables: map[string]*checkpoints.TidbTableInfo{
+				"tbl1": {
+					Name: "tbl1",
+				},
+			},
+		},
+		"test2": {
+			Name: "test2",
+			Tables: map[string]*checkpoints.TidbTableInfo{
+				"tbl1": {
+					Name: "tbl1",
+				},
+			},
+		},
+	}
+	rc.cfg.Checkpoint.Enable = true
+	rc.checkpointsDB = checkpoints.NewFileCheckpointsDB(filepath.Join(dir, "cp.pb"))
+	err = rc.checkpointsDB.Initialize(ctx, cfg, dbInfos)
+	c.Check(err, IsNil)
+	db, mock, err = sqlmock.New()
+	c.Assert(err, IsNil)
+	rc.tidbGlue = glue.NewExternalTiDBGlue(db, mysql.ModeNone)
+	// only need to check the one that is not in checkpoint
+	mock.ExpectQuery("select 1 from `test1`.`tbl2` limit 1").
+		WillReturnRows(sqlmock.NewRows([]string{""}).RowError(0, sql.ErrNoRows))
+	err = rc.checkTableEmpty(ctx)
+	c.Assert(err, IsNil)
+	c.Assert(mock.ExpectationsWereMet(), IsNil)
+}
+
 func (s *checkInfoSuite) TestLocalResource(c *C) {
 	dir := c.MkDir()
 	mockStore, err := storage.NewLocalStorage(dir)

br/pkg/lightning/restore/meta_manager.go

@@ -1027,9 +1027,65 @@ func (m noopTableMetaMgr) UpdateTableBaseChecksum(ctx context.Context, checksum
 }
 
 func (m noopTableMetaMgr) CheckAndUpdateLocalChecksum(ctx context.Context, checksum *verify.KVChecksum, hasLocalDupes bool) (bool, bool, *verify.KVChecksum, error) {
-	return false, false, nil, nil
+	return true, true, &verify.KVChecksum{}, nil
 }
 
 func (m noopTableMetaMgr) FinishTable(ctx context.Context) error {
 	return nil
 }
+
+type singleMgrBuilder struct{}
+
+func (b singleMgrBuilder) Init(context.Context) error {
+	return nil
+}
+
+func (b singleMgrBuilder) TaskMetaMgr(pd *pdutil.PdController) taskMetaMgr {
+	return &singleTaskMetaMgr{
+		pd: pd,
+	}
+}
+
+func (b singleMgrBuilder) TableMetaMgr(tr *TableRestore) tableMetaMgr {
+	return noopTableMetaMgr{}
+}
+
+type singleTaskMetaMgr struct {
+	pd *pdutil.PdController
+}
+
+func (m *singleTaskMetaMgr) InitTask(ctx context.Context, source int64) error {
+	return nil
+}
+
+func (m *singleTaskMetaMgr) CheckTasksExclusively(ctx context.Context, action func(tasks []taskMeta) ([]taskMeta, error)) error {
+	_, err := action(nil)
+	return err
+}
+
+func (m *singleTaskMetaMgr) CheckAndPausePdSchedulers(ctx context.Context) (pdutil.UndoFunc, error) {
+	return m.pd.RemoveSchedulers(ctx)
+}
+
+func (m *singleTaskMetaMgr) CheckTaskExist(ctx context.Context) (bool, error) {
+	return true, nil
+}
+
+func (m *singleTaskMetaMgr) CheckAndFinishRestore(context.Context, bool) (shouldSwitchBack bool, shouldCleanupMeta bool, err error) {
+	return true, true, nil
+}
+
+func (m *singleTaskMetaMgr) Cleanup(ctx context.Context) error {
+	return nil
+}
+
+func (m *singleTaskMetaMgr) CleanupTask(ctx context.Context) error {
+	return nil
+}
+
+func (m *singleTaskMetaMgr) CleanupAllMetas(ctx context.Context) error {
+	return nil
+}
+
+func (m *singleTaskMetaMgr) Close() {
+}