【环境说明】
上游（阿里云RDS)：mysql 5.6.16-log
下游TiDB：v4.0.13
DM版本：v2.0.4
【DDL操作】
表结构：
CREATE TABLE mc_activity_assist_support (
id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
activity_id bigint(20) NOT NULL
cycle_no varchar(100) NOT NULL,
city_code varchar(20) NOT NULL,
user_no bigint(20) NOT NULL,
user_phone varchar(15) NOT NULL DEFAULT ‘’ ,
launch_user_no bigint(20) NOT NULL ,
launch_user_phone varchar(15) NOT NULL DEFAULT ‘’ ,
user_type tinyint(3) unsigned NOT NULL DEFAULT ‘2’ ,
nick_name varchar(255) NOT NULL DEFAULT ‘’,
headimg varchar(255) NOT NULL DEFAULT ‘’ ,
assist_status tinyint(3) unsigned NOT NULL DEFAULT ‘0’ ,
snapshot_info text DEFAULT NULL ,
award_info text DEFAULT NULL,
create_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘创建时间’,
update_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT ‘更新时间’,
PRIMARY KEY (id),
KEY idx_activity_user (activity_id,cycle_no,user_no,user_type),
KEY idx_activity_lanuch_user (activity_id,cycle_no,launch_user_no,user_type),
KEY idx_create_time (create_time),
KEY idx_update_time (update_time),
KEY idx_activity_phone (activity_id,user_phone),
KEY idx_activity_launch_phone (activity_id,launch_user_phone),
KEY idx_activity_user_no (activity_id,user_no),
KEY idx_activity_launch_user_no (activity_id,launch_user_no)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin AUTO_INCREMENT=8279262;
使用gh-ost添加如下索引：
ALTER TABLE marketing_center.mc_activity_assist_support ADD INDEX idx_activity_create_time(activity_id, create_time)
【复制报错】
[2021/08/08 02:19:26.702 +08:00] [ERROR] [streamer_controller.go:259] [“meet error when get binlog event”] [task=dm-rds_master] [unit=“binlog replication”] [error=“io.CopyN failed. err unexpected EOF, copied 0, expected 79: connection was bad”] [errorVerbose=“connection was bad
github.com/go-mysql-org/go-mysql/mysql.init
\t/go/pkg/mod/github.com/go-mysql-org/go-mysql@v1.1.3-0.20210519094347-5ec8d511f5be/mysql/error.go:10
runtime.doInit
\t/usr/local/go/src/runtime/proc.go:5222
runtime.doInit
\t/usr/local/go/src/runtime/proc.go:5217
runtime.doInit
\t/usr/local/go/src/runtime/proc.go:5217
runtime.doInit
\t/usr/local/go/src/runtime/proc.go:5217
runtime.main
\t/usr/local/go/src/runtime/proc.go:190
runtime.goexit
\t/usr/local/go/src/runtime/asm_amd64.s:1357
io.CopyN failed. err unexpected EOF, copied 0, expected 79
github.com/go-mysql-org/go-mysql/packet.(*Conn).ReadPacketTo
\t/go/pkg/mod/github.com/go-mysql-org/go-mysql@v1.1.3-0.20210519094347-5ec8d511f5be/packet/conn.go:151
github.com/go-mysql-org/go-mysql/packet.(*Conn).ReadPacketReuseMem
\t/go/pkg/mod/github.com/go-mysql-org/go-mysql@v1.1.3-0.20210519094347-5ec8d511f5be/packet/conn.go:98
github.com/go-mysql-org/go-mysql/packet.(*Conn).ReadPacket
\t/go/pkg/mod/github.com/go-mysql-org/go-mysql@v1.1.3-0.20210519094347-5ec8d511f5be/packet/conn.go:90
github.com/go-mysql-org/go-mysql/replication.(*BinlogSyncer).onStream
\t/go/pkg/mod/github.com/go-mysql-org/go-mysql@v1.1.3-0.20210519094347-5ec8d511f5be/replication/binlogsyncer.go:662
runtime.goexit
\t/usr/local/go/src/runtime/asm_amd64.s:1357”]
[2021/08/08 02:19:26.702 +08:00] [ERROR] [syncer.go:1507] [“fail to fetch binlog”] [task=dm-rds_master] [unit=“binlog replication”] [error=“io.CopyN failed. err unexpected EOF, copied 0, expected 79: connection was bad”]
详细见日志：worker.log (653.7 KB)
【问题】
从数据库监控上看当时并没有发现数据库指标异常，报错时binlog文件也是正常的，没有损坏的情况；出现这个中断一般是什么导致的？是否是触发了某个bug？
附binlog情况：
