diff --git a/pkg/checksum/checker.go b/pkg/checksum/checker.go
index 790b336..5fc5e5b 100644
--- a/pkg/checksum/checker.go
+++ b/pkg/checksum/checker.go
@@ -170,6 +170,9 @@ func (c *Checker) RecentValue() string {
 }
 
 func (c *Checker) GetLowWatermark() (string, error) {
+	if c.chunker == nil {
+		return "", errors.New("chunker not initialized")
+	}
 	return c.chunker.GetLowWatermark()
 }
 
diff --git a/pkg/checksum/checker_test.go b/pkg/checksum/checker_test.go
index 76f5d91..abeca61 100644
--- a/pkg/checksum/checker_test.go
+++ b/pkg/checksum/checker_test.go
@@ -258,3 +258,36 @@ func TestChangeDataTypeDatetime(t *testing.T) {
 	assert.NoError(t, err)
 	assert.NoError(t, checker.Run(context.Background())) // fails
 }
+
+func TestFromWatermark(t *testing.T) {
+	testutils.RunSQL(t, "DROP TABLE IF EXISTS tfromwatermark, _tfromwatermark_new, _tfromwatermark_chkpnt")
+	testutils.RunSQL(t, "CREATE TABLE tfromwatermark (a INT NOT NULL, b INT, c INT, PRIMARY KEY (a))")
+	testutils.RunSQL(t, "CREATE TABLE _tfromwatermark_new (a INT NOT NULL, b INT, c INT, PRIMARY KEY (a))")
+	testutils.RunSQL(t, "CREATE TABLE _tfromwatermark_chkpnt (a INT)") // for binlog advancement
+	testutils.RunSQL(t, "INSERT INTO tfromwatermark VALUES (1, 2, 3)")
+	testutils.RunSQL(t, "INSERT INTO _tfromwatermark_new VALUES (1, 2, 3)")
+
+	db, err := dbconn.New(testutils.DSN(), dbconn.NewDBConfig())
+	assert.NoError(t, err)
+
+	t1 := table.NewTableInfo(db, "test", "tfromwatermark")
+	assert.NoError(t, t1.SetInfo(context.TODO()))
+	t2 := table.NewTableInfo(db, "test", "_tfromwatermark_new")
+	assert.NoError(t, t2.SetInfo(context.TODO()))
+	logger := logrus.New()
+
+	cfg, err := mysql.ParseDSN(testutils.DSN())
+	assert.NoError(t, err)
+	feed := repl.NewClient(db, cfg.Addr, t1, t2, cfg.User, cfg.Passwd, &repl.ClientConfig{
+		Logger:          logger,
+		Concurrency:     4,
+		TargetBatchTime: time.Second,
+	})
+	assert.NoError(t, feed.Run())
+
+	config := NewCheckerDefaultConfig()
+	config.Watermark = "{\"Key\":[\"a\"],\"ChunkSize\":1000,\"LowerBound\":{\"Value\": [\"2\"],\"Inclusive\":true},\"UpperBound\":{\"Value\": [\"3\"],\"Inclusive\":false}}"
+	checker, err := NewChecker(db, t1, t2, feed, config)
+	assert.NoError(t, err)
+	assert.NoError(t, checker.Run(context.Background()))
+}
diff --git a/pkg/migration/runner.go b/pkg/migration/runner.go
index 58dbf84..01609a1 100644
--- a/pkg/migration/runner.go
+++ b/pkg/migration/runner.go
@@ -42,7 +42,7 @@ const (
 
 // These are really consts, but set to var for testing.
 var (
-	checkpointDumpInterval  = 2 * time.Second
+	checkpointDumpInterval  = 50 * time.Second
 	tableStatUpdateInterval = 5 * time.Minute
 	statusInterval          = 30 * time.Second
 	sentinelCheckInterval   = 1 * time.Second
diff --git a/pkg/migration/runner_test.go b/pkg/migration/runner_test.go
index ca98c49..adaac15 100644
--- a/pkg/migration/runner_test.go
+++ b/pkg/migration/runner_test.go
@@ -955,6 +955,75 @@ func TestCheckpointRestore(t *testing.T) {
 	assert.True(t, r2.usedResumeFromCheckpoint)
 }
 
+func TestCheckpointResumeDuringChecksum(t *testing.T) {
+	tbl := `CREATE TABLE cptresume (
+		id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
+		id2 INT NOT NULL,
+		pad VARCHAR(100) NOT NULL default 0)`
+	cfg, err := mysql.ParseDSN(testutils.DSN())
+	assert.NoError(t, err)
+	testutils.RunSQL(t, `DROP TABLE IF EXISTS cptresume, _cptresume_new, _cptresume_chkpnt, _cptresume_sentinel`)
+	testutils.RunSQL(t, tbl)
+	testutils.RunSQL(t, `CREATE TABLE _cptresume_sentinel (id INT NOT NULL PRIMARY KEY)`)
+	testutils.RunSQL(t, `insert into cptresume (id2,pad) SELECT 1, REPEAT('a', 100) FROM dual`)
+	testutils.RunSQL(t, `insert into cptresume (id2,pad) SELECT 1, REPEAT('a', 100) FROM cptresume`)
+	testutils.RunSQL(t, `insert into cptresume (id2,pad) SELECT 1, REPEAT('a', 100) FROM cptresume a JOIN cptresume b JOIN cptresume c`)
+
+	r, err := NewRunner(&Migration{
+		Host:            cfg.Addr,
+		Username:        cfg.User,
+		Password:        cfg.Passwd,
+		Database:        cfg.DBName,
+		Threads:         4,
+		TargetChunkTime: 100 * time.Millisecond,
+		Table:           "cptresume",
+		Alter:           "ENGINE=InnoDB",
+		Checksum:        true,
+	})
+	assert.NoError(t, err)
+
+	// Call r.Run() with our context in a go-routine.
+	// When we see that we are waiting on the sentinel table,
+	// we then manually start the first bits of checksum, and then close()
+	// We should be able to resume from the checkpoint into the checksum state.
+	ctx, cancel := context.WithCancel(context.Background())
+	// it will error as the context is cancelled
+	go r.Run(ctx) //nolint:errcheck
+	for {
+		// Wait for the sentinel table.
+		if r.getCurrentState() >= stateWaitingOnSentinelTable {
+			break
+		}
+		time.Sleep(time.Millisecond)
+	}
+
+	assert.NoError(t, r.checksum(context.TODO()))       // run the checksum, the original Run is blocked on sentinel.
+	assert.NoError(t, r.dumpCheckpoint(context.TODO())) // dump a checkpoint with the watermark.
+	cancel()                                            // unblock the original waiting on sentinel.
+	assert.NoError(t, r.Close())                        // close the run.
+
+	// drop the sentinel table.
+	testutils.RunSQL(t, `DROP TABLE _cptresume_sentinel`)
+
+	// Start again as a new runner,
+	r2, err := NewRunner(&Migration{
+		Host:            cfg.Addr,
+		Username:        cfg.User,
+		Password:        cfg.Passwd,
+		Database:        cfg.DBName,
+		Threads:         4,
+		TargetChunkTime: 100 * time.Millisecond,
+		Table:           "cptresume",
+		Alter:           "ENGINE=InnoDB",
+		Checksum:        true,
+	})
+	assert.NoError(t, err)
+	err = r2.Run(context.Background())
+	assert.NoError(t, err)
+	assert.True(t, r2.usedResumeFromCheckpoint)
+	assert.NotEmpty(t, r2.checksumWatermark) // it had a checksum watermark
+}
+
 func TestCheckpointDifferentRestoreOptions(t *testing.T) {
 	tbl := `CREATE TABLE cpt1difft1 (
 		id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,