Mysql 5.5 and 5.6 replication

What's new
in MySQL 5.5 and 5.6
replication
Giuseppe Maxia
Continuent, Inc

©Continuent 2012.

Tuesday, April 17, 12 1

AGENDA

• 5.5
• semi-synchronous replication

• 5.6
• delayed replication

• server UUID

• crash-safe slave

• multi-thread slave

• Global transaction identi!ers

©Continuent 2012 2


DA
AG
EN semi-synch replication


semi-synchronous
replication

• Available in 5.5 and higher
• Makes sure that at least one slave has
copied the data.
• Increases reliability


client
master transaction
1 with regular
commit replication

execute 2

slave
returns
4 to client
binary log 3

5 replication
5

client transaction
master
1 with semi-
commit synchronous
replication

execute 2

slave
7 returns
to client
binary log 3

sends
4 transaction relay log 5
to slave

gets
6 acknowledgement
6

semi-synchronous
replication in practice

• installation:
• it’s a plugin.

• Actually, two plugins


semi-synch replication install
# in the master
plugin-load=rpl_semi_sync_master=semisync_master.so
rpl_semi_sync_master_enabled=1

# in each slave
plugin-load=rpl_semi_sync_slave=semisync_slave.so
rpl_semi_sync_slave_enabled=1

# restar all servers


semi-synch replication check
# in the master
show variables like 'rpl_semi%';
+------------------------------------+-------+
| Variable_name | Value |
+------------------------------------+-------+
| rpl_semi_sync_master_enabled | ON |
| rpl_semi_sync_master_timeout | 10000 |
| rpl_semi_sync_master_trace_level | 32 |
| rpl_semi_sync_master_wait_no_slave | ON |
+------------------------------------+-------+


semi-synch replication check
show status like "rpl_semi_%tx";
+-----------------------------+-------+
| variable_name | value |
+-----------------------------+-------+
| RPL_SEMI_SYNC_MASTER_NO_TX | 0 |
| RPL_SEMI_SYNC_MASTER_YES_TX | 0 |
+-----------------------------+-------+


semi-synch replication test
master> create table t1 ( i int);
Query OK, 0 rows affected (0.01 sec)

master> show status like "rpl_semi_%tx";
+-----------------------------+-------+
+-----------------------------+-------+
| Rpl_semi_sync_master_no_tx | 0 |
| Rpl_semi_sync_master_yes_tx | 1 |
+-----------------------------+-------+


disabling semi-synch
# for each slave

set global rpl_semi_sync_slave_enabled=0;
stop slave io_thread;
start slave io_thread;


disabled semi-synch replication test
master> insert into t1 values (1);
Query OK, 1 row affected (10.00 sec)

+-----------------------------+-------+
+-----------------------------+-------+
+-----------------------------+-------+
2 rows in set (0.00 sec)


disabled semi-synch replication test

+-----------------------------+-------+
+-----------------------------+-------+
+-----------------------------+-------+


re-enabling semi-synch
# in one slave

set global rpl_semi_sync_slave_enabled=1;
stop slave io_thread;
start slave io_thread;


reenabled semi-synch replication test

+-----------------------------+-------+
+-----------------------------+-------+
+-----------------------------+-------+


DA
AG
EN delayed replication


delayed replication in practice
STOP SLAVE;
change master to master_delay=60;
START SLAVE;

SHOW SLAVE STATUSG
(...)
SQL_Delay: 60
SQL_Remaining_Delay: NULL


master > use test;
master > create table t2 (i int);

SHOW SLAVE STATUSG
(...)
SQL_Delay: 60
SQL_Remaining_Delay: 55

slave> SHOW TABLES FROM test;
+----------------+
| Tables_in_test |
+----------------+
| t1 |
+----------------+

# after 1 minute

SHOW SLAVE STATUSG
(...)
SQL_Delay: 60

slave> SHOW TABLES FROM test;
+----------------+
| Tables_in_test |
+----------------+
| t1 |
| t2 |
+----------------+


DA
AG
EN Server UUID


testing some replication
make_replication_sandbox mysql-5.6.5-m8-
osx10.7-.tar.gz
....
....
replication directory installed in
$HOME/sandboxes/rsandbox_mysql-5_6_5


~/sandboxes/rsandbox_mysql-5_6_5/s1
show slave statusG
******** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 127.0.0.1
Master_User: rsandbox
Master_Port: 12630
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 2524
Relay_Log_File: mysql_sandbox12631-
relay-bin.000002
Relay_Log_Pos: 2677
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes


~/sandboxes/rsandbox_mysql-5_6_5/s1
show slave statusG
....
Master_Server_Id: 1
Master_UUID: be3c022a-726f-11e1-a26a-a64f991393aa
Master_Info_File: /Users/gmax/sandboxes/
rsandbox_mysql-5_6_5/node1/data/master.info
SQL_Delay: 0
Slave_SQL_Running_State: Slave has read all relay
log; waiting for the slave I/O thread to update it


DA
AG
EN crash safe slave


uncovering replication
features
STOP SLAVE;

set global master_info_repository='table';

slave1 [localhost] {msandbox} ((none)) > set global
relay_log_info_repository='table';

slave1 [localhost] {msandbox} ((none)) > set global
slave_parallel_workers=3;


ﬁxing replication tables
use mysql;

slave1 [localhost] {msandbox} (mysql) > alter table
slave_master_info engine=innodb;
Records: 1 Duplicates: 0 Warnings: 0

slave_relay_log_info engine=innodb;

slave_worker_info engine=innodb;


Look at the new features
show slave statusG
....
....
Master_UUID: be3c022a-726f-11e1-a26a-
a64f991393aa
Master_Info_File:
mysql.slave_master_info


select * from mysql.slave_master_infoG
*************************** 1. row ******
Master_id: 101
Number_of_lines: 22
Master_log_name: mysql-bin.000001
Master_log_pos: 2524
Host: 127.0.0.1
User_name: rsandbox
User_password: rsandbox
Port: 12630
....
Heartbeat: 1800
Bind:
Ignored_server_ids: 0
Uuid: be3c022a-726f-11e1-a26a-a64f991393aa
Retry_count: 86400


select * from mysql.slave_relay_log_infoG
*************************** 1. row ***************
Master_id: 101
Number_of_lines: 6
Relay_log_name: ./mysql_sandbox12631-relay-bin.
000002
Relay_log_pos: 2677
Sql_delay: 0
Number_of_workers: 3


select * from mysql.slave_worker_infoG
************** 3. row *********************
Master_id: 101
Worker_id: 2
Relay_log_name: ./mysql_sandbox12631-relay-
bin.000003
Relay_log_pos: 1394
Checkpoint_relay_log_name: ./mysql_sandbox12631-relay-
bin.000003
Checkpoint_relay_log_pos: 1199
Checkpoint_master_log_name: mysql-bin.000001
Checkpoint_master_log_pos: 3456
Checkpoint_seqno: 0
Checkpoint_group_size: 64
Checkpoint_group_bitmap:


DA
AG
EN multi-threaded slave


facts about multiple threaded slave
a.k.a. parallel replication

• Requires MySQL 5.6 in both master and
slave
• Parallel replication with a 5.5 master will
slow down replication
• Data gets parallelized by schema


enabling multi-threaded slave
set global slave_parallel_workers=10;

show variables like '%worker%';
+------------------------+-------+
+------------------------+-------+
| slave_parallel_workers | 10 |
+------------------------+-------+

stop slave; start slave;


DA
AG
EN global transaction identiﬁer


global transaction identiﬁer
• Requires MySQL 5.6 in both master and slave
• requires all servers in the cluster to run these
options:
• log-bin
• log-slave-updates
• gtid-mode=ON
• disable-gtid-unsafe-statements


global transaction identiﬁer issues

• Can't work with:
• non-transactional updates.
• temporary tables within transactions
• CREATE TABLE ... SELECT
• disable-gtid-unsafe-statements will make the server
fail on any of the above cases.


enabling global transaction identiﬁers
# change my.cnf in ALL nodes
# (master and slaves)

[mysqld]
log-bin
log-slave-updates
gtid-mode=ON
disable-gtid-unsafe-statements

# restart the servers


testing global transaction identiﬁers
create table t1 (i int not null primary key);
show binlog eventsG
********* 3. row ***************************
Log_name: mysql-bin.000002
Pos: 147
Event_type: Gtid
Server_id: 1
End_log_pos: 191
Info: SET
@@SESSION.GTID_NEXT='44556A96-8417-11E1-9589-2BD5ACDD51FD:1'
********* 4. row ***************************
Log_name: mysql-bin.000002
Pos: 191
Event_type: Query
Server_id: 1
End_log_pos: 305
Info: use `test`; create table t1 (i int not null primary
key)


testing global transaction identiﬁers
SHOW SLAVE STATUSG
(...)
Retrieved_Gtid_Set: 44556A96-8417-11E1-9589-2BD5ACDD51FD:1-2
Executed_Gtid_Set: 44556A96-8417-11E1-9589-2BD5ACDD51FD:1-2


DEMO


WE ARE HIRING!
• Cluster implementation engineer
• QA engineer
• Documentation writer

http://www.continuent.com/about/careers

©Continuent 2012 44


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