MySQL 5.1 Replication

Replication with MySQL 5.1
Ligaya Turmelle
Senior Technical Support Engineer - MySQL
[email_address]
http://joind.in/1573
<Insert Picture Here>

Agenda
What it is
How it Works
Types
Use Cases
Setting it up
Filtering Rules
Monitoring
<Insert Picture Here>

What is it? <Insert Picture Here>

How does it work? <Insert Picture Here>

At a high level
On the master
makes a change to the data
writes it to the binary log
On the slave
copies the masters binary logs to the relay logs
runs the relay logs applying the changes

Nitty Gritty of Master Side
Master makes a change and writes the binlog entry
Details:
it writes the the changes to the binary log
writes the transactions serially
After writing to the binary log, the master tells the storage engine to commit the transaction.

Enter the Slave IO thread
Slave creates an I/O thread which connects to the master
Slave connects to the master just like any other client then starts a binlog dump process
Master then creates a thread to send the binary log contents to a slave when the slave connects
Slave IO thread writes the binary log events to the slaves relay log
Once slave catches up with master, IO thread goes to sleep and waits for the master to signal it has new events

Slave SQL Thread
Separates the actual execution of the binary log events from the retrieval of it on the master
Read and replays the events from the relay log
updates the slaves data to match the masters
Has all privileges so it can run any query that is sent
potential bottleneck

Types <Insert Picture Here>

Basic Info
3 binary log formats:
Statement Based Replication (SBR)
Row Based Replication (RBR)
Mixed
The format of the binary log has no relevance to how the slave handles it. The SQL thread on the slave can and will handle any binary log format given to it
controlled by setting the binlog_format
each format has its pros and cons

Statement Based Replication (SBR)
Been used by all previous versions of replication
Pros:
Proven
Less data written to log files.
Can be used for audit purposes
Cons:
Some statements are unsafe
Any nondeterministic behavior is difficult to replicate
More locking may be needed then Row Based
Complex statements will have to be evaluated and executed
Deterministic UDFs must be applied on the slaves
InnoDB: INSERT statement using AUTO_INCREMENT blocks other nonconflicting INSERT statements.

Row Based Replication (RBR)
Replicates only the changed rows
Pros:
All changes can be replicated
Safest form
Same as most other RDBMS
Fewer locks required
Cons:
Generally more data to be logged
Some problems with older versions but fixed now
large BLOBs can take longer to replicate

Mixed Replication
Uses both SBR and RBR
Statement-based logging is used by default
Automatically switches to row-based logging in particular cases
http://dev.mysql.com/doc/refman/5.1/en/binary-log-mixed.html
Can provide best of both worlds - but requires testing

Use Cases <Insert Picture Here>

ScaleOut
Very common use case
Scale out load to multiple servers
Reads can be sent to slaves
Writes are done on the Master
Good for high read workloads
Some improvement to writes if Master only writes

Data Redundancy
Another common usage
backups
Failover
Use as a testing system
test queries
application interaction
Use different storage engine abilities

Analytics
Reporting
different queries
long running
locking
caches
DBA can query to learn about their data
distribution
trends

Long Distance Data Distribution
Geographically separate locations
disaster recovery
Office wants to work on a local copy

Setting it up <Insert Picture Here>

Setting up Replication
On the Master config file, need to add
log-bin=mysql_bin
server_id=1
On the Slave config file, need to add
server_id=2
Create the Replication User
requires REPLICATION SLAVE privilege
mysql> CREATE USER 'repl'@'%.mydomain.com' IDENTIFIED BY 'slavepass';
mysql> GRANT REPLICATION SLAVE ON *.* TO
'repl'@'%.mydomain.com';

Setting up Replication (con’t)
Get from Master
Obtain master server binary log coordinates
mysql> FLUSH TABLES WITH READ LOCK;
mysql> SHOW MASTER STATUS;
Copy the master (if not a new master)
mysqldump or binary copy
Finally ready! Actual steps for a new setup:
Configure Master; (re)start Master
Set up Replication User on Master
Get Master status
Release read locks on Master
Configure Slave; (re)start Slave
Execute CHANGE MASTER TO statement

mysql> CHANGE MASTER TO -> MASTER_HOST=' master_host_name ', -> MASTER_USER=' replication_user_name ', -> MASTER_PASSWORD=' replication_password ', -> [ MASTER_PORT = port_num,] -> MASTER_LOG_FILE=' recorded_log_file_name ', -> MASTER_LOG_POS= recorded_log_position, -> [MASTER_SSL = {0|1},] -> [MASTER_SSL_CA = ' ca_file_name ',] -> [MASTER_SSL_CAPATH = ' ca_directory_name ',] -> [MASTER_SSL_CERT = ' cert_file_name ',] -> [MASTER_SSL_KEY = ' key_file_name ',] -> [MASTER_SSL_CIPHER = ' cipher_list ',] -> [MASTER_SSL_VERIFY_SERVER_CERT = {0|1}] ;

Filtering rules <Insert Picture Here>

Filtering Rule Basics
2 levels of filtering
On the Master
Not recommended
On the slave
preferred
Can be confusing

Filtering on the Master
How it works:
binlog-do-db
binlog-ignore-db
Not recommended - ever!
Reasons:
audit
point in time recovery
crash recovery

Filtering on the Slave
How it works:
replicate-do-db
replicate-ignore-db
replicate-do-table
replicate-ignore-table
replicate-wild-do-table
replicate-wild-ignore-table
Avoid mixing “do” and “ignore” command
Avoid mixing wildcard and nonwildcard options
First checks DB level filtering and only if no matches moves on to the table level matching

Database Filters Filters

Table Filters 1 Start (Following DB options) Any replicate-*-table options? execute UPDATE and Exit Which logging format? Statement Row For each statement that performs an update.. For each update of a table row... No Yes

Table Filters 2 (do/ignore) Any replicate-do-table options? execute UPDATE and Exit Any replicate-ignore-table options? Does the table match any of them? Yes No Yes No ignore UPDATE and Exit Does the table match any of them? Yes Yes No No

Table Filters 3 (wild do/wild ignore) Any replicate-wild-do-table options? execute UPDATE and Exit Any replicate-wild-ignore-table options? Does the table match any of them? Yes No Yes No ignore UPDATE and Exit Does the table match any of them? Yes Yes No No

Table Filters 4 Is there another table to be tested? Any replicate-do-table or replicate-wild-do-table options? Yes No No ignore UPDATE and Exit Yes execute UPDATE and Exit

Monitoring <Insert Picture Here>

mysql> SHOW SLAVE STATUSG *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: localhost Master_User: root Master_Port: 3306 Connect_Retry: 3 Master_Log_File: gbichot-bin.005 Read_Master_Log_Pos: 79 Relay_Log_File: gbichot-relay-bin.005 Relay_Log_Pos: 548 Relay_Master_Log_File: gbichot-bin.005 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: On the Slave

On the Slave Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 79 Relay_Log_Space: 552 Until_Condition: None Until_Log_File: Last_SQL_Error: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 8 Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error:

Questions? <Insert Picture Here>

http://nomyself.info	24
http://www.technicaltunes.com	21
http://www.slideshare.net	19
http://learn.thruhere.net	4
http://178.79.146.129	2
http://www.lmodules.com	1

MySQL 5.1 Replication

by Ligaya Turmelle on May 21, 2010

Accessibility

Categories

Tags

Upload Details

Usage Rights

6 Embeds 71

Statistics

MySQL 5.1 Replication — Presentation Transcript