MGR主从不一致问题排查与修复

运行环境

linux：CentOS release 6.8 (Final)

kernel：2.6.32-642.6.2.el6.x86_64

mysql Server version: 5.7.21-20-log Percona Server (GPL)，MGR单主模式

1.故障现象

解析binlog

mysqlbinlog -v --base64-output=DECODE-ROWS mysql-bin.000042 --include-gtids='1bb1b861-f776-11e6-3319-010204058070:113111655'

1bb1b861-f776-11e6-3319-010204058070:113111655 该GTID的binlog内容 ycc01 与ycc03服务器内容一致

ycc01.prod.bj2 mysql_3319

SET @@SESSION.GTID_NEXT= '1bb1b861-f776-11e6-3319-010204058070:113111655'/*!*/;

# at

# :: server id  end_log_pos  Query thread_id= exec_time= error_code=

SET TIMESTAMP=/*!*/;

BEGIN

/*!*/;

# at

# :: server id  end_log_pos  Table_map: `ycc_cfcenter`.`config_center_client_list` mapped to number

# at

# :: server id  end_log_pos  Delete_rows: table id  flags: STMT_END_F

### DELETE FROM `ycc_cfcenter`.`config_center_client_list`

### WHERE

### @=

### @=

### @='10.1.97.131'

### @=''

### @=

# at

# :: server id  end_log_pos  Xid =

COMMIT/*!*/;

ycc03.prod.bj2 mysql_3319

SET @@SESSION.GTID_NEXT= '1bb1b861-f776-11e6-3319-010204058070:113111655'/*!*/;

# at

# :: server id  end_log_pos  Query thread_id= exec_time= error_code=

SET TIMESTAMP=/*!*/;

BEGIN

/*!*/;

# at

# :: server id  end_log_pos  Table_map: `ycc_cfcenter`.`config_center_client_list` mapped to number

# at

# :: server id  end_log_pos  Delete_rows: table id  flags: STMT_END_F

### DELETE FROM `ycc_cfcenter`.`config_center_client_list`

### WHERE

### @=

### @=

### @='10.1.97.131'

### @=''

### @=

# at

# :: server id  end_log_pos  Xid =

COMMIT/*!*/;

mysqlbinlog -v --base64-output=DECODE-ROWS mysql-bin.000042 --include-gtids='1bb1b861-f776-11e6-3319-010204058070:113111656'

1bb1b861-f776-11e6-3319-010204058070:113111656 该GTID的binlog内容 ycc01 与ycc03服务器内容不一致

ycc01.db.prod.bj2 mysql_3319

SET @@SESSION.GTID_NEXT= '1bb1b861-f776-11e6-3319-010204058070:113111656'/*!*/;

# at

# :: server id  end_log_pos  Query thread_id= exec_time= error_code=

SET TIMESTAMP=/*!*/;

BEGIN

/*!*/;

# at

# :: server id  end_log_pos  Table_map: `ycc_cfcenter`.`config_center_client_list` mapped to number

# at

# :: server id  end_log_pos  Delete_rows: table id  flags: STMT_END_F

### DELETE FROM `ycc_cfcenter`.`config_center_client_list`

### WHERE

### @=

### @=

### @='10.1.94.137'

### @=''

### @=

# at

# :: server id  end_log_pos  Xid =

COMMIT/*!*/;

ycc03.db.prod.bj2 mysql_3319

SET @@SESSION.GTID_NEXT= '1bb1b861-f776-11e6-3319-010204058070:113111656'/*!*/;

# at

# :: server id  end_log_pos  Query thread_id= exec_time= error_code=

SET TIMESTAMP=/*!*/;

BEGIN

/*!*/;

# at

# :: server id  end_log_pos  Table_map: `ycc_cfcenter`.`config_center_client_list` mapped to number

# at

# :: server id  end_log_pos  Write_rows: table id  flags: STMT_END_F

### INSERT INTO `ycc_cfcenter`.`config_center_client_list`

### SET

### @=

### @=

### @='10.1.97.131'

### @=''

### @=

# at

# :: server id  end_log_pos  Xid =

COMMIT/*!*/;

2.原因排查

官方已经反馈社区版MySQL 5.7.26和MySQL 8.0.16 中会修复，如果是企业版客户可以申请最新的hotfix版本。

在未升级 MySQL 版本前，若再发生此类故障，在修复时需要人工检查，检查切换时binlog中 GTID 信息与新主节点对应 GTID 的信息是否一致。

如果不一致需要人工修复至一致状态，一致才可以将被踢出的原主节点加回集群。

参考文档

https://mp.weixin.qq.com/s/WuYRp2DU2uRq0vN-b29PPA?client=tim&ADUIN=190100183&ADSESSION=1555029984&ADTAG=CLIENT.QQ.5603_.0&ADPUBNO=26882

3.修复过程

3.1 确定故障点

查看故障节点error.log

error.log

2019-04-12T12:41:45.834694+08:00 3561943 [ERROR] Slave SQL for channel 'group_replication_applier': Could not execute Write_rows event on table ycc_cfcenter.config_center_client_list; Duplicate entry '1

36-10.1.94.137-5566' for key 'uniq_idx_project_id', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event's master log FIRST, end_log_pos 327, Error_code: 1062

2019-04-12T12:41:45.834713+08:00 3561943 [Warning] Slave: Duplicate entry '136-10.1.94.137-5566' for key 'uniq_idx_project_id' Error_code: 1062

查看故障节点当前GTID

故障节点当前GTID

SHOW MASTER STATUS

FILE               POSITION  Binlog_Do_DB  Binlog_Ignore_DB  Executed_Gtid_Set

---------------- --------- ------------ ---------------- --------------------------------------------------

mysql-bin.000042 747898223 1bb1b861-f776-11e6-3319-010204058070:1-113111661

解析故障节点包含【1bb1b861-f776-11e6-3319-010204058070:1-113111661】 GTID 的binlog
##mysqlbinlog -vvv relay-bin-group_replication_applier.000053 --include-gtids="1bb1b861-f776-11e6-3319-010204058070:113111661"

故障节点binlog解析

SET @@SESSION.GTID_NEXT= '1bb1b861-f776-11e6-3319-010204058070:113111661'/*!*/;

# at 703004277

#190412 12:41:45 server id 58070 end_log_pos 81 Query thread_id=4163376 exec_time=0 error_code=0

SET TIMESTAMP=1555044105/*!*/;

BEGIN

/*!*/;

# at 703004358

#190412 12:41:45 server id 58070 end_log_pos 161 Table_map: `ycc_cfcenter`.`config_center_client_list` mapped to number 108

# at 703004438

#190412 12:41:45 server id 58070 end_log_pos 327 Write_rows: table id 108 flags: STMT_END_F

BINLOG '

'/*!*/;

### INSERT INTO `ycc_cfcenter`.`config_center_client_list`

### SET

### @1=380183781 /* LONGINT meta=0 nullable=0 is_null=0 */

### @2=206 /* LONGINT meta=0 nullable=1 is_null=0 */

### @3='10.1.97.133' /* VARSTRING(300) meta=300 nullable=1 is_null=0 */

### @4='5566' /* VARSTRING(90) meta=90 nullable=1 is_null=0 */

### @5=1555044105821 /* LONGINT meta=0 nullable=1 is_null=0 */

### INSERT INTO `ycc_cfcenter`.`config_center_client_list`

### SET

### @1=380183788 /* LONGINT meta=0 nullable=0 is_null=0 */

### @2=136 /* LONGINT meta=0 nullable=1 is_null=0 */

### @3='10.1.94.137' /* VARSTRING(300) meta=300 nullable=1 is_null=0 */

### @4='5566' /* VARSTRING(90) meta=90 nullable=1 is_null=0 */

### @5=1555044105821 /* LONGINT meta=0 nullable=1 is_null=0 */

### INSERT INTO `ycc_cfcenter`.`config_center_client_list`

### SET

### @1=380183795 /* LONGINT meta=0 nullable=0 is_null=0 */

### @2=206 /* LONGINT meta=0 nullable=1 is_null=0 */

### @3='10.1.97.131' /* VARSTRING(300) meta=300 nullable=1 is_null=0 */

### @4='5566' /* VARSTRING(90) meta=90 nullable=1 is_null=0 */

### @5=1555044105821 /* LONGINT meta=0 nullable=1 is_null=0 */

# at 703004604

#190412 12:41:45 server id 58070 end_log_pos 354 Xid = 604665142

COMMIT/*!*/;

解析主节点binlog 确定相同内容binlog event 对应的GTID值
##mysqlbinlog -vvv mysql-bin.000042 --include-gtids="1bb1b861-f776-11e6-3319-010204058070:113111660-113111665'

主库binlog解析

SET @@SESSION.GTID_NEXT= '1bb1b861-f776-11e6-3319-010204058070:113111662'/*!*/;

# at 418536376

#190412 12:41:45 server id 58070 end_log_pos 418536457 Query thread_id=4163376 exec_time=0 error_code=0

SET TIMESTAMP=1555044105/*!*/;

BEGIN

/*!*/;

# at 418536457

#190412 12:41:45 server id 58070 end_log_pos 418536537 Table_map: `ycc_cfcenter`.`config_center_client_list` mapped to number 108

# at 418536537

#190412 12:41:45 server id 58070 end_log_pos 418536703 Write_rows: table id 108 flags: STMT_END_F

BINLOG '

'/*!*/;

### INSERT INTO `ycc_cfcenter`.`config_center_client_list`

### SET

### @1=380183781 /* LONGINT meta=0 nullable=0 is_null=0 */

### @2=206 /* LONGINT meta=0 nullable=1 is_null=0 */

### @3='10.1.97.133' /* VARSTRING(300) meta=300 nullable=1 is_null=0 */

### @4='5566' /* VARSTRING(90) meta=90 nullable=1 is_null=0 */

### @5=1555044105821 /* LONGINT meta=0 nullable=1 is_null=0 */

### INSERT INTO `ycc_cfcenter`.`config_center_client_list`

### SET

### @1=380183788 /* LONGINT meta=0 nullable=0 is_null=0 */

### @2=136 /* LONGINT meta=0 nullable=1 is_null=0 */

### @3='10.1.94.137' /* VARSTRING(300) meta=300 nullable=1 is_null=0 */

### @4='5566' /* VARSTRING(90) meta=90 nullable=1 is_null=0 */

### @5=1555044105821 /* LONGINT meta=0 nullable=1 is_null=0 */

### INSERT INTO `ycc_cfcenter`.`config_center_client_list`

### SET

### @1=380183795 /* LONGINT meta=0 nullable=0 is_null=0 */

### @2=206 /* LONGINT meta=0 nullable=1 is_null=0 */

### @3='10.1.97.131' /* VARSTRING(300) meta=300 nullable=1 is_null=0 */

### @4='5566' /* VARSTRING(90) meta=90 nullable=1 is_null=0 */

### @5=1555044105821 /* LONGINT meta=0 nullable=1 is_null=0 */

# at 418536703

#190412 12:41:45 server id 58070 end_log_pos 418536730 Xid = 604665142

COMMIT/*!*/;

3.2 确定故障点结果汇总

1.故障节点提示 Duplicate entry '136-10.1.94.137-5566' for key 'uniq_idx_project_id' 有唯一约束冲突

2.故障节点当前GTID 【1bb1b861-f776-11e6-3319-010204058070:1-113111660】

3.故障节点与主节点GTID相差一个值，相同binlog event 主节点GTID【1bb1b861-f776-11e6-3319-010204058070:113111662】故障节点【1bb1b861-f776-11e6-3319-010204058070:113111661】

3.3 故障节点修复过程

3.3.1 停止故障节点MGR服务
STOP group_replication;
SET GLOBAL super_read_only=0
3.3.2 删除冲突键数据
DELETE FROM config_center_client_list WHERE project_id=136 AND client_ip='10.1.94.137' AND PORT=5566
3.3.3 清除故障节点GTID信息
RESET MASTER
3.3.4 重置故障节点GTID信息,故障节点因唯一约束冲突未重做的binlog event，在主节点对应的GTID为【1bb1b861-f776-11e6-3319-010204058070:113111662】。
SET @@GLOBAL.GTID_PURGED='1bb1b861-f776-11e6-3319-010204058070:1-113111661';
START group_replication;
SHOW MASTER STATUS

3.3.5 在故障节点执行, 需要跳过的GTID只有一个,也可以用以下方法,这样就不需要reset masert。

STOP group_replication;
SET GLOBAL super_read_only=0
set sql_log_bin=0
DELETE FROM config_center_client_list WHERE project_id=136 AND client_ip='10.1.94.137' AND PORT=5566
set sql_log_bin=1
set session gtid_next="1bb1b861-f776-11e6-3319-010204058070:113111661";
begin;commit;
set session gtid_next="AUTOMATIC";
START group_replication;