add indices & USE INDEX clause

migration/current.go

@@ -28,6 +28,7 @@ func Migrations() []*gormigrate.Migration {
 		v15(), // 外部ログイン機能追加
 		v16(), // パーミッション修正
 		v17(), // ユーザーホームチャンネル
+		v18(), // インデックス追加
 	}
 }
 
@@ -140,6 +141,8 @@ func AllCompositeIndexes() [][]string {
 		{"idx_files_channel_id_created_at", "files", "channel_id", "created_at"},
 		{"idx_files_creator_id_created_at", "files", "creator_id", "created_at"},
 		{"idx_messages_stamps_user_id_stamp_id_updated_at", "messages_stamps", "user_id", "stamp_id", "updated_at"},
+		{"idx_channel_channels_id_is_public_is_forced", "channels", "id", "is_public", "is_forced"},
+		{"idx_messages_deleted_at_created_at", "messages", "deleted_at", "created_at"},
 	}
 }
 

migration/v18.go

@@ -0,0 +1,26 @@
+package migration
+
+import (
+	"github.com/jinzhu/gorm"
+	"gopkg.in/gormigrate.v1"
+)
+
+// v18 インデックス追加
+func v18() *gormigrate.Migration {
+	return &gormigrate.Migration{
+		ID: "18",
+		Migrate: func(db *gorm.DB) error {
+			// 複合インデックス
+			indexes := [][]string{
+				{"idx_channels_channels_id_is_public_is_forced", "channels", "id", "is_public", "is_forced"},
+				{"idx_messages_deleted_at_created_at", "messages", "deleted_at", "created_at"},
+			}
+			for _, c := range indexes {
+				if err := db.Table(c[1]).AddIndex(c[0], c[2:]...).Error; err != nil {
+					return err
+				}
+			}
+			return nil
+		},
+	}
+}

repository/message_impl.go

@@ -190,6 +190,24 @@ func (repo *GormRepository) GetMessages(query MessagesQuery) (messages []*model.
 		tx = tx.Order("messages.created_at DESC")
 	}
 
+	if query.Offset > 0 {
+		tx = tx.Offset(query.Offset)
+	}
+
+	if query.ExcludeDMs && query.Channel == uuid.Nil && query.User == uuid.Nil && query.ChannelsSubscribedByUser == uuid.Nil && !query.Since.Valid && !query.Until.Valid && query.Limit > 0 {
+		// アクティビティ用にUSE INDEX指定でクエリ発行
+		// TODO 綺麗じゃない
+		err = tx.
+			Limit(query.Limit + 1).
+			Raw("SELECT messages.* FROM messages USE INDEX (idx_messages_deleted_at_created_at) INNER JOIN channels ON messages.channel_id = channels.id WHERE messages.deleted_at IS NULL AND channels.is_public = true").
+			Scan(&messages).
+			Error
+		if len(messages) > query.Limit {
+			return messages[:len(messages)-1], true, err
+		}
+		return messages, false, err
+	}
+
 	if query.ChannelsSubscribedByUser != uuid.Nil || query.ExcludeDMs {
 		tx = tx.Joins("INNER JOIN channels ON messages.channel_id = channels.id")
 	}
@@ -224,10 +242,6 @@ func (repo *GormRepository) GetMessages(query MessagesQuery) (messages []*model.
 		tx = tx.Where("channels.is_public = true")
 	}
 
-	if query.Offset > 0 {
-		tx = tx.Offset(query.Offset)
-	}
-
 	if query.Limit > 0 {
 		err = tx.Limit(query.Limit + 1).Find(&messages).Error
 		if len(messages) > query.Limit {