From 3712de9bb7aef6b9c7120194f5abc3df207aa26e Mon Sep 17 00:00:00 2001
From: Leavrth <jianjun.liao@outlook.com>
Date: Mon, 29 Jan 2024 10:53:44 +0800
Subject: [PATCH 1/2] create database by db pool

Signed-off-by: Leavrth <jianjun.liao@outlook.com>
---
 br/pkg/restore/client.go      | 35 ++++++++++++++++++++++++++++++-----
 br/pkg/restore/client_test.go |  2 +-
 br/pkg/task/restore.go        |  7 ++-----
 3 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/br/pkg/restore/client.go b/br/pkg/restore/client.go
index 1a9bdfd9af4e9..2d6e64e059ea1 100644
--- a/br/pkg/restore/client.go
+++ b/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 with db")
+		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.
diff --git a/br/pkg/restore/client_test.go b/br/pkg/restore/client_test.go
index 4407a90d07b35..c291440e9bf1d 100644
--- a/br/pkg/restore/client_test.go
+++ b/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)))
 }
 
diff --git a/br/pkg/task/restore.go b/br/pkg/task/restore.go
index bc60b155ec101..1932034f9156e 100644
--- a/br/pkg/task/restore.go
+++ b/br/pkg/task/restore.go
@@ -923,11 +923,8 @@ 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.

From f123984a8a4202ddd60d12ed18bbf5b48ff26008 Mon Sep 17 00:00:00 2001
From: Jianjun Liao <36503113+Leavrth@users.noreply.github.com>
Date: Wed, 7 Feb 2024 10:33:46 +0800
Subject: [PATCH 2/2] Update br/pkg/restore/client.go

Co-authored-by: 3pointer <qdlc2010@gmail.com>
---
 br/pkg/restore/client.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/br/pkg/restore/client.go b/br/pkg/restore/client.go
index 2d6e64e059ea1..295dd1832cf91 100644
--- a/br/pkg/restore/client.go
+++ b/br/pkg/restore/client.go
@@ -860,7 +860,7 @@ func (rc *Client) CreateDatabases(ctx context.Context, dbs []*metautil.Database)
 	}
 
 	if len(rc.dbPool) == 0 {
-		log.Info("create databases with db")
+		log.Info("create databases sequentially")
 		for _, db := range dbs {
 			err := rc.createDatabaseWithDBConn(ctx, db.Info, rc.db)
 			if err != nil {