This document discusses MySQL multi-source replication, which enables a replication slave to receive transactions from multiple masters simultaneously. It provides configuration steps for setting up a MariaDB/Percona Server database as a multi-source replication slave, including ensuring unique server IDs and GTID domains for each master, defining replication connections, and enabling parallel replication threads to optimize transaction processing from multiple sources.

1. MySQL Multi-Source Replication
Wagner Bianchi - wagner.bianchi@percona.com
Principal Technical Services Engineer
Max Bubenick - max.bubenick@percona.com
Technical Operations Manager

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This is gonna be a multi-source replication walkthrough on MariaDB and Percona Server

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● enables a replication slave to receive transactions from multiple
sources/masters simultaneously;
● aggregate data from multiple servers - Data Mart/Data Warehouse;
● merge table shards - no auto_increment conflict control;
● can be carefully used connecting many location on one geo-positioned
cluster;
● centralize all data for backup propose.

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● No gtid_mode variable to turn on GTID
● Binary logs has positions and GTIDs
• CHANGE MASTER ‘’ TO
• CHANGE MASTER 'foo' TO
• CHANGE MASTER TO
● MASTER_USE_GTID=CURRENT_POS|SLAVE_POS
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● Accessed using SHOW ALL SLAVES STATUS;
● SET @@default_master_connection works well;
set @@default_master_connection=''; -- default slave connection
show status like 'Slave_running';
set @@default_master_connection='connection_name01'; -- named connection name
show status like 'Slave_running';

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box01
Multi-Source Slave
box02
box03
box04
MariaDB [(none)]> pager egrep "Connection|Gtid"
PAGER set to 'egrep "Connection|Seconds"'
MariaDB [(none)]> show all slaves statusG
Connection_name: box02
Gtid_IO_Pos: 1-1-63,3-3-1
Gtid_Slave_Pos: 1-1-63,3-3-1
Connection_name: box03
Gtid_IO_Pos: 1-1-63,3-3-1
Gtid_Slave_Pos: 1-1-63,3-3-1
Connection_name: box04
Gtid_IO_Pos: 1-1-63,3-3-1
Gtid_Slave_Pos: 1-1-63,3-3-1
3 rows in set (0.00 sec)
On the multi-source slave side:
● Use SHOW ALL SLAVES STATUSG
● Use @@default_master_connection
● Use STOP/START ALL SLAVES
● Use STOP/START SLAVE 'box02'

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#: box01 - multi-source slave
[client]
port=3306
socket=/var/lib/mysql/mysql.sock
[mysqld]
user=mysql
port=3306
socket=/var/lib/mysql/mysql.sock
basedir=/usr
datadir=/var/lib/mysql
read_only=1
#: repl vars
server_id=1
report_host=box01
report_port=3306
report_user=repl
log_bin=mysql-bin
log_bin_index=mysql.index
log_slave_updates=true
binlog_format=ROW
#: verify checksum on master
master_verify_checksum=1
#: gtid vars
gtid_domain_id=1
gtid_ignore_duplicates=ON
gtid_strict_mode=1
#: msr slave parallel mode *
box02.slave_parallel_mode=optimistic
box03.slave_parallel_mode=optimistic
box04.slave_parallel_mode=optimistic
#: other slave variables
slave_parallel_threads=16
slave_domain_parallel_threads=4
slave_parallel_max_queued=512M
slave_net_timeout=15
slave_sql_verify_checksum=1
slave_compressed_protocol=1
#: binary log group commit behavior
#binlog_commit_wait_usec=100000
#binlog_commit_wait_count=20

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#: box01
MariaDB [(none)]> select @@server_id,@@gtid_domain_idG
*************** 1. row ***************************
@@server_id: 1
@@gtid_domain_id: 1
1 row in set (0.00 sec)
#: box02
MariaDB [(none)]> select @@server_id,@@gtid_domain_idG
*************** 1. row ***************************
@@server_id: 2
@@gtid_domain_id: 2
1 row in set (0.00 sec)
#: box03
MariaDB [(none)]> select @@server_id,@@gtid_domain_idG
*************** 1. row ***************************
@@server_id: 3
@@gtid_domain_id: 3
1 row in set (0.00 sec)
#: box04
MariaDB [(none)]> select @@server_id,@@gtid_domain_idG
*************** 1. row ***************************
@@server_id: 4
@@gtid_domain_id: 4
1 row in set (0.00 sec)
box01
Multi-Source Slave
gtid_domain_id=1
gtid_domain_id=2
gtid_domain_id=3
gtid_domain_id=4

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● Make sure the replication user is set on all the servers;
● Make sure all the servers has unique server_id and gtid_domain_id;
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#: Connection name with box02
MariaDB [(none)]> change master 'box02' to master_host='192.168.0.102',
master_user='repl', master_password='Bi@nchI', master_use_gtid=current_pos;
#: Connection name with box03
MariaDB [(none)]> change master 'box03' to master_host='192.168.0.103',
master_user='repl', master_password='Bi@nchI', master_use_gtid=current_pos;
#: Connection name with box04
MariaDB [(none)]> change master 'box04' to master_host='192.168.0.104',
master_user='repl', master_password='Bi@nchI', master_use_gtid=current_pos;

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# start all slaves
MariaDB [(none)]> start all slaves;
Query OK, 0 rows affected, 3 warnings (0.02 sec)
MariaDB [(none)]> show warnings;
+-------+------+-----------------------+
| Level | Code | Message |
+-------+------+-----------------------+
| Note | 1937 | SLAVE 'box04' started |
| Note | 1937 | SLAVE 'box03' started |
| Note | 1937 | SLAVE 'box02' started |
+-------+------+-----------------------+
3 rows in set (0.00 sec)
MariaDB [(none)]> stop all slaves;
Query OK, 0 rows affected, 3 warnings (0.02 sec)

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#: setting the @@default_master_connection
MariaDB [(none)]> set @@default_master_connection='box02';
Query OK, 0 rows affected (0.00 sec)
#: showing some box02 Connection name's status replication variables
MariaDB [(none)]> pager egrep "Slave_IO_State|Using_Gtid|Gtid_IO_Pos"
PAGER set to 'egrep "Slave_IO_State|Using_Gtid|Gtid_IO_Pos"'
MariaDB [(none)]> show slave statusG
Slave_IO_State: Waiting for master to send event
Using_Gtid: Current_Pos
Gtid_IO_Pos: 1-1-64,2-2-1,3-3-1
1 row in set (0.00 sec)
#: starting and stopping just box02, as per @@default_master_connection set
MariaDB [(none)]> stop slave;
Query OK, 0 rows affected (0.01 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.02 sec)

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#: relay logs - one group for each set connection name - host+relay-bin+connection_name
-rw-rw---- 1 mysql mysql 306 Mar 23 00:32 maria01-relay-bin-box02.000001
-rw-rw---- 1 mysql mysql 663 Mar 23 00:32 maria01-relay-bin-box02.000002
-rw-rw---- 1 mysql mysql 66 Mar 23 00:32 maria01-relay-bin-box02.index
-rw-rw---- 1 mysql mysql 306 Mar 23 00:32 maria01-relay-bin-box03.000001
-rw-rw---- 1 mysql mysql 663 Mar 23 00:32 maria01-relay-bin-box03.000002
-rw-rw---- 1 mysql mysql 66 Mar 23 00:32 maria01-relay-bin-box03.index
-rw-rw---- 1 mysql mysql 306 Mar 23 00:32 maria01-relay-bin-box04.000001
-rw-rw---- 1 mysql mysql 663 Mar 23 00:32 maria01-relay-bin-box04.000002
-rw-rw---- 1 mysql mysql 66 Mar 23 00:32 maria01-relay-bin-box04.index
#: master.info - one per set connection name - master-connection_name.info
-rw-rw---- 1 mysql mysql 153 Mar 23 00:32 master-box02.info
-rw-rw---- 1 mysql mysql 153 Mar 23 00:32 master-box03.info
-rw-rw---- 1 mysql mysql 153 Mar 23 00:32 master-box04.info
#: multi-master.info file, listing all set connections names
-rw-rw---- 1 mysql mysql 18 Feb 15 11:00 multi-master.info
[root@maria01 mysql]# cat multi-master.info #: don't edit this file :)
box02
box03
box04

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#: check gtid_current and gtid_slave pos variables
MariaDB [mysql]> select @@gtid_current_pos, @@gtid_slave_posG
*************************** 1. row ***************************
@@gtid_current_pos: 1-1-64,2-2-1,3-3-1
@@gtid_slave_pos: 1-1-64,2-2-1,3-3-1
1 row in set (0.00 sec)
#: check current clave current and slave pos from mysql.gtid_slave_pos table
MariaDB [mysql]> select * from mysql.gtid_slave_pos;
+-----------+--------+-----------+--------+
| domain_id | sub_id | server_id | seq_no |
+-----------+--------+-----------+--------+
| 1 | 16 | 1 | 63 |
| 1 | 20 | 1 | 64 |
| 3 | 1 | 3 | 1 |
+-----------+--------+-----------+--------+
3 rows in set (0.00 sec)

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• @@GTID_CURRENT_POS
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● CHANGE MASTER 'foo' TO … MASTER_USE_GTID=CURRENT_POS;
● @@GTID_STRICT_MODE=1
#: checking global variable @@gtid_current_pos
MariaDB [(none)]> SELECT @@GTID_CURRENT_POS,@@GTID_STRICT_MODEG
*************************** 1. row ***************************
@@GTID_CURRENT_POS: 1-1-68,2-2-149378,3-3-88622,4-4-98365
@@GTID_STRICT_MODE: 1 -- help keeping binlogs identical across multiple servers
1 row in set (0.00 sec)

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• @@GTID_SLAVE_POS CHANGE MASTER
TO
• CHANGE MASTER 'foo' TO … MASTER_USE_GTID=SLAVE_POS;
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#: checking global variable @@gtid_slave_pos
MariaDB [(none)]> SELECT @@GTID_SLAVE_POSG
*************************** 1. row ***************************
@@GTID_SLAVE_POS: 1-1-66,2-2-149378,3-3-88622,4-4-98365
1 row in set (0.00 sec)
#: checking global variable @@gtid_slave_pos (can't be set per Connection Name)
MariaDB [(none)]> SET GLOBAL GTID_SLAVE_POS='1-1-66,2-2-149378,3-3-88622,4-4-98365';
Query OK, 0 rows affected, 3 warnings (0.01 sec)
#: SHOULD BE DONE AFTER STOPPING REPLICATION CONNECTION NAMES...

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#: comparing both @@gtid_current_pos and @@gtid_slave_pos
MariaDB [(none)]> SELECT @@GLOBAL.GTID_CURRENT_POS,@@GLOBAL.GTID_SLAVE_POSG
*************************** 1. row ***************************
@@GLOBAL.GTID_CURRENT_POS: 1-1-71,2-2-149378,3-3-88622,4-4-98365 -- 5 ADDITIONAL TRXs
@@GLOBAL.GTID_SLAVE_POS: 1-1-66,2-2-149378,3-3-88622,4-4-98365
1 row in set (0.00 sec)
#: setting dynamically @@gtid_slave_pos - TRANSACTIONS CANNOT BE REPLAYED
MariaDB [(none)]> SET GLOBAL GTID_SLAVE_POS='1-1-66,2-2-149378,3-3-88622,4-4-98365';
ERROR 1947 (HY000): Specified GTID 1-1-66 conflicts with the binary log which contains
a more recent GTID 1-1-71. If MASTER_GTID_POS=CURRENT_POS is used, the binlog position
will override the new value of @@gtid_slave_pos.
#: command above was embraced by START/STOP ALL SLAVES.

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● slave_parallel_threads sets the number of threads will take care
about the updates on relay logs based on their timestamps;
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#: making a multi-source slave multi-threaded
MariaDB [(none)]> stop all slaves;
Query OK, 0 rows affected, 3 warnings (0.00 sec)
MariaDB [(none)]> set global slave_parallel_threads=12;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> set global slave_domain_parallel_threads=4;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> start all slaves;
Query OK, 0 rows affected, 3 warnings (0.03 sec)
MariaDB [(none)]> select @@slave_parallel_mode,@@slave_parallel_threads,@@slave_domain_parallel_threadsG
*************************** 1. row ***************************
@@slave_parallel_mode: optimistic # will retry transaction in case of parallelism conflicts
@@slave_parallel_threads: 12 # total of threads available for slave to execute relay logs
@@slave_domain_parallel_threads: 4 # minimum # of thread used for a domain_id all time
1 row in set (0.00 sec)

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#: making a multi-source slave multi-threaded
MariaDB [(none)]> SELECT ID,TIME,STATE,USER FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER='system user';
+----+------+------------------------------------------------------------------+-------------+
| ID | TIME | STATE | USER |
+----+------+------------------------------------------------------------------+-------------+
| 18 | 452 | Waiting for master to send event | system user |
| 17 | 364 | Slave has read all relay log; waiting for the slave I/O thread t | system user |
| 16 | 452 | Waiting for master to send event | system user |
| 15 | 364 | Slave has read all relay log; waiting for the slave I/O thread t | system user |
| 14 | 364 | Slave has read all relay log; waiting for the slave I/O thread t | system user |
| 13 | 452 | Waiting for master to send event | system user |
| 12 | 452 | Waiting for work from SQL thread | system user |
| 11 | 452 | Waiting for work from SQL thread | system user |
| 10 | 0 | Update_rows_log_event::ha_update_row(-1) | system user |
| 9 | 0 | Unlocking tables | system user |
| 8 | 452 | Waiting for work from SQL thread | system user |
| 7 | 452 | Waiting for work from SQL thread | system user |
| 6 | 0 | Update_rows_log_event::ha_update_row(-1) | system user |
| 5 | 0 | Update_rows_log_event::ha_update_row(-1) | system user |
| 4 | 0 | Update_rows_log_event::ha_update_row(-1) | system user |
| 3 | 0 | Update_rows_log_event::ha_update_row(-1) | system user |
+----+------+------------------------------------------------------------------+-------------+
16 rows in set (0.07 sec)

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● binlog_commit_wait_usec=100000
● binlog_commit_wait_count=20
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#: binary logs for group commit
[root@maria02 mysql]# mysqlbinlog mysql-bin.000017 -vvvv | egrep "cid=353579"
#160325 21:37:27 server id 2 end_log_pos 27101572 GTID 2-2-149349 cid=353579 trans
#160325 21:37:27 server id 2 end_log_pos 27103107 GTID 2-2-149350 cid=353579 trans
#160325 21:37:27 server id 2 end_log_pos 27104646 GTID 2-2-149351 cid=353579 trans
#160325 21:37:27 server id 2 end_log_pos 27106181 GTID 2-2-149352 cid=353579 trans
#160325 21:37:27 server id 2 end_log_pos 27107716 GTID 2-2-149353 cid=353579 trans
#160325 21:37:27 server id 2 end_log_pos 27109251 GTID 2-2-149354 cid=353579 trans
MariaDB [(none)]> show global status where variable_name in
('Binlog_commits','Binlog_group_commits');
+----------------------+-------+
| Variable_name | Value |
+----------------------+-------+
| Binlog_commits | 39681 |
| Binlog_group_commits | 5523 |
+----------------------+-------+
2 rows in set (0.02 sec)
the bigger the difference between the two variables
the bigger the apparent group commit efficiency

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● One can restart both threads or just SQL_THREAD;
#: adding new schema to box02
box02> set sql_log_bin=0; create database if not exists box02_new; set sql_log_bin=1;
Query OK, 0 rows affected (0.00 sec)
Query OK, 1 row affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
#: adding filters on multi-source slave
box01> stop slave 'box02'; set global box02.replicate_ignore_db='box02_new'; start slave 'box02';
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
#: remove filter
box01> stop slave; set global box02.replicate_ignore_db=''; start slave;
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.11 sec)

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• sql_slave_skip_counter
● If parallel replication is enabled:
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● Stop all slaves, turn off the parallel replication and skip_counter;
● Set a new value for @@GLOBAL.GTID_SLAVE_POS;
MariaDB [box02]> set default_master_connection='box02'; set global sql_slave_skip_counter=1;
Query OK, 0 rows affected (0.00 sec)
ERROR 1966 (HY000): When using parallel replication and GTID with multiple replication domains,
@@sql_slave_skip_counter can not be used. Instead, setting @@gtid_slave_pos explicitly can be used to skip
to after a given GTID position.
MariaDB [box02]> stop all slaves; set @@global.gtid_slave_pos='1-1-71,2-2-149382,3-3-88623,4-4-98365';
Query OK, 0 rows affected, 3 warnings (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
MariaDB [box02]> start all slaves;
Query OK, 0 rows affected, 3 warnings (0.01 sec)

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● gtid_mode=on
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● PERFORMANCE_SCHEMA
● SHOW SLAVE STATUS
● SHOW SLAVE STATUS FOR CHANNEL
mysql> pager egrep "Slave_IO|Channel"
PAGER set to 'egrep "Slave_IO|Channel"'
mysql> show slave statusG
Slave_IO_State: Waiting for master to send event
Slave_IO_Running: Yes
Channel_Name: box02
Slave_IO_State: Waiting for master to send event
Slave_IO_Running: Yes
Channel_Name: box03
Slave_IO_State: Waiting for master to send event
Slave_IO_Running: Yes
Channel_Name: box04
3 rows in set (0.00 sec)

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box01
Multi-Source Slave
box02
box03
box04
#: multi-source slave configuration file
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
report_host=box01
report_port=3306
report_user=repl
#: gtid configuration
server_id=1
gtid_mode=on
log_bin=mysql-bin
log_bin_index=mysql-bin.index
log_slave_updates=true
enforce_gtid_consistency
#: binary logs (GROUP COMMIT)
binlog_group_commit_sync_delay=100000
binlog_group_commit_sync_no_delay_cont=20
#binlog_order_commits=0 # increase parallelism
#: repositories for crash-safe
master_info_repository=TABLE
relay_log_info_repository=TABLE
#: slave configs
slave_parallel_workers=4
slave_parallel_type='LOGICAL_CLOCK'
slave_compressed_protocol=1
slave_pending_jobs_size_max=256M

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#: Replication Channel for box02
box01> change master to master_host='192.168.0.12', master_user='repl',
master_password='Bi@nchI', master_auto_position=1 for channel 'box02';
#: Replication Channel for box03
box01> change master to master_host='192.168.0.13', master_user='repl',
master_password='Bi@nchI', master_auto_position=1 for channel 'box03';
#: Replication Channel for box04
box01> change master to master_host='192.168.0.14', master_user='repl',
master_password='Bi@nchI', master_auto_position=1 for channel 'box04';

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#: relay logs - one group for each set connection name
-rw-r----- 1 mysql mysql 847 Mar 27 00:51 percona01-relay-bin-box02.000018
-rw-r----- 1 mysql mysql 534 Mar 27 00:51 percona01-relay-bin-box02.000019
-rw-r----- 1 mysql mysql 70 Mar 27 00:51 percona01-relay-bin-box02.index
-rw-r----- 1 mysql mysql 597 Mar 27 00:51 percona01-relay-bin-box03.000017
-rw-r----- 1 mysql mysql 534 Mar 27 00:51 percona01-relay-bin-box03.000018
-rw-r----- 1 mysql mysql 70 Mar 27 00:51 percona01-relay-bin-box03.index
-rw-r----- 1 mysql mysql 550 Mar 27 00:51 percona01-relay-bin-box04.000017
-rw-r----- 1 mysql mysql 487 Mar 27 00:51 percona01-relay-bin-box04.000018
-rw-r----- 1 mysql mysql 70 Mar 27 00:51 percona01-relay-bin-box04.index
#:No master.info file as it needs to be configured with crash-safe, repos as TABLE
mysql> show variables where variable_name in
('master_info_repository','relay_log_info_repository');
+---------------------------+-------+
| Variable_name | Value |
+---------------------------+-------+
| master_info_repository | TABLE |
| relay_log_info_repository | TABLE |
+---------------------------+-------+
2 rows in set (0.00 sec)
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#: stopping all slaves
mysql> stop slave;
Query OK, 0 rows affected (0.06 sec)
mysql> show slave statusG
Slave_IO_Running: No
Slave_SQL_Running: No
[...snip...]
3 rows in set (0.00 sec)
#: stopping just one specific slave
mysql> stop slave for channel 'box02';
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status for channel 'box02'G
Slave_IO_Running: No
Slave_SQL_Running: No
Slave_SQL_Running_State:
1 row in set (0.00 sec)

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#: starting all slaves
mysql> start slave;
Query OK, 0 rows affected (0.06 sec)
mysql> show slave statusG
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
[...snip...]
3 rows in set (0.00 sec)
#: starting just one specific slave
mysql> start slave for channel 'box02';
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status for channel 'box02'G
Slave_IO_Running: No
Slave_SQL_Running: No
Slave_SQL_Running_State:
1 row in set (0.00 sec)

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#: show all slaves status
mysql> show slave statusG
Channel_Name: box02
Channel_Name: box03
Channel_Name: box04
3 rows in set (0.00 sec)
#: show slave status for a specific slave
mysql> show slave status for channel 'box02'G
Slave_IO_State: Waiting for master to send event
Retrieved_Gtid_Set: 61be13a1-d574-11e5-83c7-0800274fb806:1-61...
Executed_Gtid_Set: 4bd77dee-d572-11e5-b09f-0800274fb806:1-56...
Channel_Name: box02
1 row in set (0.00 sec)

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#: PERFORMANCE_SCHEMA replication tables
mysql> show tables from performance_schema like 'replication%';
+---------------------------------------------+
| Tables_in_performance_schema (replication%) |
+---------------------------------------------+
| replication_applier_configuration |
| replication_applier_status |
| replication_applier_status_by_coordinator |
| replication_applier_status_by_worker |
| replication_connection_configuration |
| replication_connection_status |
| replication_group_member_stats |
| replication_group_members |
+---------------------------------------------+
8 rows in set (0.00 sec)

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#: PERFORMANCE_SCHEMA replication tables
mysql> select channel_name,service_state,last_heartbeat_timestamp
-> from performance_schema.replication_connection_statusG
*************************** 1. row ***************************
channel_name: box02
service_state: ON
last_heartbeat_timestamp: 2016-03-26 22:22:39
*************************** 2. row ***************************
channel_name: box03
service_state: ON
last_heartbeat_timestamp: 2016-03-26 22:22:30
*************************** 3. row ***************************
channel_name: box04
service_state: ON
last_heartbeat_timestamp: 2016-03-26 22:22:31
3 rows in set (0.00 sec)

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mysql> select @@slave_parallel_workers, @@slave_parallel_type;
+--------------------------+-----------------------+
| @@slave_parallel_workers | @@slave_parallel_type |
+--------------------------+-----------------------+
| 8 | LOGICAL_CLOCK |
+--------------------------+-----------------------+
1 row in set (0.00 sec)
#: PERFORMANCE_SCHEMA, checking coordinators state (multi-threaded slaves)
mysql> select channel_name, service_state
-> from performance_schema.replication_applier_status_by_coordinatorG
*************************** 1. row ***************************
channel_name: box02
service_state: ON
*************************** 2. row ***************************
channel_name: box03
service_state: ON
*************************** 3. row ***************************
channel_name: box04
service_state: ON
3 rows in set (0.00 sec)

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#: PERFORMANCE_SCHEMA, checking coordinators state (multi-threaded slaves)
mysql> select channel_name,thread_id,service_state,last_seen_transaction
-> from performance_schema.replication_applier_status_by_worker
-> where last_seen_transaction<>''G
*************************** 1. row ***************************
channel_name: box03
thread_id: 71
service_state: ON
last_seen_transaction: ab001313-d573-11e5-bc39-0800274fb806:2536
*************************** 2. row ***************************
channel_name: box03
thread_id: 72
service_state: ON
last_seen_transaction: ab001313-d573-11e5-bc39-0800274fb806:2537
*************************** 3. row ***************************
channel_name: box03
thread_id: 73
service_state: ON
last_seen_transaction: ab001313-d573-11e5-bc39-0800274fb806:2538
...

37. www.percona.com
• CHANGE REPLICATION FILTER
#: adding new schema to box02
box02> set sql_log_bin=0; create database if not exists box02_new; set sql_log_bin=1;
Query OK, 0 rows affected (0.00 sec)
Query OK, 1 row affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
#: adding filters on multi-source slave
mysql> stop slave; change replication filter replicate_ignore_db=(box02_new); start slave;
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.11 sec)
#: remove filter
mysql> stop slave; change replication filter replicate_ignore_db=(); start slave;
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.11 sec)

38. www.percona.com
•
• REPLICATE_DO_DB
• REPLICATE_IGNORE_DB
• REPLICATE_DO_TABLE
• REPLICATE_IGNORE_TABLE
• REPLICATE_WILD_DO_TABLE
• REPLICATE_WILD_IGNORE_TABLE
• REPLICATE_REWRITE_DB
•
•
● http://bugs.mysql.com/bug.php?id=80843

39. www.percona.com
#: rewriting updates on db A to db B
box01> stop slave; change replication filter replicate_rewrite_db=((box02,box03)); start slave;
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.07 sec)
#: writing some data to A to be routed to B
box02> insert into box02.t1 set i=10;
Query OK, 1 row affected (1.01 sec)
#: checking data on A
box01> select * from box02.t1;
Empty set (0.00 sec)
#: checking data on B
box01> select * from box03.t1G
*************************** 1. row ***************************
i: 10
1 row in set (0.00 sec)
#: remove filter
box01> stop slave; change replication filter replicate_rewrite_db=(); start slave;
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.12 sec)
● REPLICATE_REWRITE_DB

40. www.percona.com
•
●
●
box01> SELECT @@HOSTNAME,ID,USER,STATE,TIME,INFO
-> FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER='system user';
+------------+----+-------------+--------------------------------------------------------+------+------+
| @@HOSTNAME | ID | USER | STATE | TIME | INFO |
+------------+----+-------------+--------------------------------------------------------+------+------+
| box01 | 32 | system user | Waiting for an event from Coordinator | 721 | NULL |
| box01 | 33 | system user | Waiting for an event from Coordinator | 721 | NULL |
| box01 | 34 | system user | Waiting for an event from Coordinator | 721 | NULL |
| box01 | 35 | system user | Waiting for an event from Coordinator | 721 | NULL |
| box01 | 36 | system user | Waiting for an event from Coordinator | 721 | NULL |
| box01 | 25 | system user | Waiting for an event from Coordinator | 721 | NULL |
| box01 | 26 | system user | Waiting for an event from Coordinator | 721 | NULL |
| box01 | 27 | system user | Waiting for master to send event | 721 | NULL |
[...snip...]
+------------+----+-------------+--------------------------------------------------------+------+------+
30 rows in set (0.00 sec)

41. www.percona.com
•
UUID()
mysql> select * from performance_schema.replication_applier_status_by_workerG
*************************** 1. row ***************************
CHANNEL_NAME: box02
WORKER_ID: 1
THREAD_ID: NULL
SERVICE_STATE: OFF
LAST_SEEN_TRANSACTION: fa11b361-d572-11e5-b63e-0800274fb806:66
LAST_ERROR_NUMBER: 1062
LAST_ERROR_MESSAGE: Worker 0 failed executing transaction 'fa11b361-d572-11e5-b63e-
0800274fb806:66' at master log mysql-bin.000008, end_log_pos 793; Could not execute Write_rows event on table
box02.t1; Duplicate entry '1' for key 'PRIMARY', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the
event's master log mysql-bin.000008, end_log_pos 793
LAST_ERROR_TIMESTAMP: 2016-04-21 00:18:14
mysql> stop slave for channel 'box02'; set gtid_next='fa11b361-d572-11e5-b63e-0800274fb806:66'; begin;
commit; set gtid_next=automatic; start slave for channel 'box02';
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (1.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.02 sec)

42. www.percona.com
Feature MariaDB MySQL 5.7
Multi-Source Slave
Creation
CHANGE MASTER 'name' TO...; CHANGE MASTER TO … FOR CHANNEL 'name';
Parallel Threads slave_parallel_mode=optimistic
slave_parallel_threads=16 # ALL
slave_domain_parallel_threads=4
slave_parallel_max_queued=512M
slave_parallel_workers=4 # per RC
slave_parallel_type='LOGICAL_CLOCK'
slave_pending_jobs_size_max=256M
Replication Filters set global box02.
replicate_ignore_db='foo';
CHANGE REPLICATION FILTER ...
Skip Replication Errors SET GLOBAL GTID_SLAVE_POS='1-1-66';
SET GLOBAL
slave_exec_mode='IDEMPOTENT';
SET GLOBAL sql_slave_skip_counter=1;
SET GLOBAL slave_exec_mode='IDEMPOTENT';
SET GTID_NEXT='UUID:TRX_ID'
SET GLOBAL sql_slave_skip_counter=1; start
slave for channel 'xxxx'; (NO GTID)
Possible number of
sources/masters
You can for now only have 64 masters
256 replication channels for any combination
of hostname and port

43. www.percona.com