br: create database by db pool (#50771)

close pingcap/tidb#50767

br/pkg/restore/client.go

@@ -852,13 +852,38 @@ func (rc *Client) GetDBSchema(dom *domain.Domain, dbName model.CIStr) (*model.DB
 	return info.SchemaByName(dbName)
 }
 
-// CreateDatabase creates a database.
-func (rc *Client) CreateDatabase(ctx context.Context, db *model.DBInfo) error {
+// CreateDatabases creates databases. If the client has the db pool, it would create it.
+func (rc *Client) CreateDatabases(ctx context.Context, dbs []*metautil.Database) error {
 	if rc.IsSkipCreateSQL() {
-		log.Info("skip create database", zap.Stringer("name", db.Name))
+		log.Info("skip create database")
 		return nil
 	}
 
+	if len(rc.dbPool) == 0 {
+		log.Info("create databases sequentially")
+		for _, db := range dbs {
+			err := rc.createDatabaseWithDBConn(ctx, db.Info, rc.db)
+			if err != nil {
+				return errors.Trace(err)
+			}
+		}
+		return nil
+	}
+
+	log.Info("create databases in db pool", zap.Int("pool size", len(rc.dbPool)))
+	eg, ectx := errgroup.WithContext(ctx)
+	workers := utils.NewWorkerPool(uint(len(rc.dbPool)), "DB DDL workers")
+	for _, db_ := range dbs {
+		db := db_
+		workers.ApplyWithIDInErrorGroup(eg, func(id uint64) error {
+			conn := rc.dbPool[id%uint64(len(rc.dbPool))]
+			return rc.createDatabaseWithDBConn(ectx, db.Info, conn)
+		})
+	}
+	return eg.Wait()
+}
+
+func (rc *Client) createDatabaseWithDBConn(ctx context.Context, db *model.DBInfo, conn *DB) error {
 	log.Info("create database", zap.Stringer("name", db.Name))
 
 	if !rc.supportPolicy {
@@ -868,12 +893,12 @@ func (rc *Client) CreateDatabase(ctx context.Context, db *model.DBInfo) error {
 	}
 
 	if db.PlacementPolicyRef != nil {
-		if err := rc.db.ensurePlacementPolicy(ctx, db.PlacementPolicyRef.Name, rc.policyMap); err != nil {
+		if err := conn.ensurePlacementPolicy(ctx, db.PlacementPolicyRef.Name, rc.policyMap); err != nil {
 			return errors.Trace(err)
 		}
 	}
 
-	return rc.db.CreateDatabase(ctx, db)
+	return conn.CreateDatabase(ctx, db)
 }
 
 // CreateTables creates multiple tables, and returns their rewrite rules.

br/pkg/restore/client_test.go

@@ -137,7 +137,7 @@ func TestCheckTargetClusterFresh(t *testing.T) {
 	ctx := context.Background()
 	require.NoError(t, client.CheckTargetClusterFresh(ctx))
 
-	require.NoError(t, client.CreateDatabase(ctx, &model.DBInfo{Name: model.NewCIStr("user_db")}))
+	require.NoError(t, client.CreateDatabases(ctx, []*metautil.Database{{Info: &model.DBInfo{Name: model.NewCIStr("user_db")}}}))
 	require.True(t, berrors.ErrRestoreNotFreshCluster.Equal(client.CheckTargetClusterFresh(ctx)))
 }
 

br/pkg/task/restore.go

@@ -930,11 +930,8 @@ func runRestore(c context.Context, g glue.Glue, cmdName string, cfg *RestoreConf
 		return nil
 	}
 
-	for _, db := range dbs {
-		err = client.CreateDatabase(ctx, db.Info)
-		if err != nil {
-			return errors.Trace(err)
-		}
+	if err = client.CreateDatabases(ctx, dbs); err != nil {
+		return errors.Trace(err)
 	}
 
 	// We make bigger errCh so we won't block on multi-part failed.