From 3e560576937057d86622b2a68860985e96bbb474 Mon Sep 17 00:00:00 2001
From: luancheng <luancheng@pingcap.com>
Date: Mon, 23 Mar 2020 21:21:24 +0800
Subject: [PATCH] *: do not return error when backup/restore data is empty

---
 pkg/backup/client.go      |  3 ++-
 pkg/backup/schema_test.go |  8 ++++----
 pkg/restore/db.go         |  5 +++--
 pkg/task/backup.go        |  4 ++++
 pkg/task/restore.go       | 10 +++++++---
 5 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/pkg/backup/client.go b/pkg/backup/client.go
index 9693b6b5f..a5efe9408 100644
--- a/pkg/backup/client.go
+++ b/pkg/backup/client.go
@@ -254,7 +254,8 @@ func BuildBackupRangeAndSchema(
 	}
 
 	if backupSchemas.Len() == 0 {
-		return nil, nil, errors.New("nothing to backup")
+		log.Info("nothing to backup")
+		return nil, nil, nil
 	}
 	return ranges, backupSchemas, nil
 }
diff --git a/pkg/backup/schema_test.go b/pkg/backup/schema_test.go
index 3b3bef897..f0dec8072 100644
--- a/pkg/backup/schema_test.go
+++ b/pkg/backup/schema_test.go
@@ -43,7 +43,7 @@ func (s *testBackupSchemaSuite) TestBuildBackupRangeAndSchema(c *C) {
 	c.Assert(err, IsNil)
 	_, backupSchemas, err := BuildBackupRangeAndSchema(
 		s.mock.Domain, s.mock.Storage, testFilter, math.MaxUint64)
-	c.Assert(err, NotNil)
+	c.Assert(err, IsNil)
 	c.Assert(backupSchemas, IsNil)
 
 	// Database is not exist.
@@ -53,15 +53,15 @@ func (s *testBackupSchemaSuite) TestBuildBackupRangeAndSchema(c *C) {
 	c.Assert(err, IsNil)
 	_, backupSchemas, err = BuildBackupRangeAndSchema(
 		s.mock.Domain, s.mock.Storage, fooFilter, math.MaxUint64)
-	c.Assert(err, NotNil)
+	c.Assert(err, IsNil)
 	c.Assert(backupSchemas, IsNil)
 
-	// Empty databse.
+	// Empty database.
 	noFilter, err := filter.New(false, &filter.Rules{})
 	c.Assert(err, IsNil)
 	_, backupSchemas, err = BuildBackupRangeAndSchema(
 		s.mock.Domain, s.mock.Storage, noFilter, math.MaxUint64)
-	c.Assert(err, NotNil)
+	c.Assert(err, IsNil)
 	c.Assert(backupSchemas, IsNil)
 
 	tk.MustExec("use test")
diff --git a/pkg/restore/db.go b/pkg/restore/db.go
index f23200033..90ad64053 100644
--- a/pkg/restore/db.go
+++ b/pkg/restore/db.go
@@ -207,10 +207,11 @@ func FilterDDLJobs(allDDLJobs []*model.Job, tables []*utils.Table) (ddlJobs []*m
 		tableIDs := make(map[int64]bool)
 		tableIDs[table.Info.ID] = true
 		tableNames := make(map[string]bool)
-		tableNames[table.Info.Name.String()] = true
+		name := fmt.Sprintf("%s:%s", table.Db.Name.String(), table.Info.Name.String())
+		tableNames[name] = true
 		for _, job := range allDDLJobs {
 			if job.BinlogInfo.TableInfo != nil {
-				name := job.SchemaName + job.BinlogInfo.TableInfo.Name.String()
+				name := fmt.Sprintf("%s:%s", job.SchemaName, job.BinlogInfo.TableInfo.Name.String())
 				if tableIDs[job.TableID] || tableNames[name] {
 					ddlJobs = append(ddlJobs, job)
 					tableIDs[job.TableID] = true
diff --git a/pkg/task/backup.go b/pkg/task/backup.go
index 5944a22a0..6c38733b8 100644
--- a/pkg/task/backup.go
+++ b/pkg/task/backup.go
@@ -127,6 +127,10 @@ func RunBackup(c context.Context, g glue.Glue, cmdName string, cfg *BackupConfig
 	if err != nil {
 		return err
 	}
+	// nothing to backup
+	if ranges == nil {
+		return nil
+	}
 
 	ddlJobs := make([]*model.Job, 0)
 	if cfg.LastBackupTS > 0 {
diff --git a/pkg/task/restore.go b/pkg/task/restore.go
index 7d5dd6846..eee6434b9 100644
--- a/pkg/task/restore.go
+++ b/pkg/task/restore.go
@@ -122,9 +122,6 @@ func RunRestore(c context.Context, g glue.Glue, cmdName string, cfg *RestoreConf
 	if err != nil {
 		return err
 	}
-	if len(files) == 0 {
-		return errors.New("all files are filtered out from the backup archive, nothing to restore")
-	}
 
 	var newTS uint64
 	if client.IsIncremental() {
@@ -141,6 +138,13 @@ func RunRestore(c context.Context, g glue.Glue, cmdName string, cfg *RestoreConf
 	if err != nil {
 		return errors.Trace(err)
 	}
+
+	// nothing to restore, maybe only ddl changes in incremental restore
+	if len(files) == 0 {
+		log.Info("all files are filtered out from the backup archive, nothing to restore")
+		return nil
+	}
+
 	rewriteRules, newTables, err := client.CreateTables(mgr.GetDomain(), tables, newTS)
 	if err != nil {
 		return err