Continuent Tungsten clusters use the Tungsten Connector to ensure your applications transparently connect to the master. This enables failover and seamless switching of masters for maintenance. However, you can do far more. Tungsten Connector allows you to make better use of hardware by load balancing SQL traffic to slaves. There is also a wealth of configuration settings to help Tungsten Connector manage connections efficiently. Learn standard deployment patterns, how to create users, control load balancing, how to distribute reads across local and remote sites, and other configuration tricks. We also provide advice about how to adapt your applications to use load balancing more efficiently. Course Topics - Deployment options and techniques - Configuring users with regard to data services - Application configuration samples - Read/write splitting options and demos - Load balancing strategies - Optimization of connection and request speed - Understanding and fixing connectivity issues

1. Tungsten University:
Unleashing the Power of
Tungsten Connectors
Gilles Rayrat, Director of Operations/France
©Continuent 2013

2. What is Tungsten Connector?
Native
protocol
App COM_QUERY
COM_INIT_DB
COM_DROP_DB
Connector
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3. A Key Tungsten Component
• Provide access to the master
• Handle database failures
• Can access slaves for reads
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4. Deployments
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5. Deployment 1: app servers
App Server App Server App Server App Server App Server
+ Connector + Connector + Connector + Connector + Connector
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6. Deployment 2: database servers
App Server App Server App Server App Server App Server App Server
...
Software Load Balancer
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7. Deployment 3: dedicated hosts
App Server App Server App Server App Server App Server App Server
...
Hardware Load Balancer
...
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8. Deployment best practice
Install with port 3306!
tools/tpm con!gure <data service name>
<options>
--connector-listen-port=3306
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9. Closer view
• Performance
• Failure handling
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10. Packet Streaming
• Fast operations, Low overhead
• Full transparency
Protocol packet
COM_QUERY
select * from t
App
Connector
Protocol packet
OK
ResultSet Rows:1
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11. Closer view
• Performance
• Failure handling
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12. Connector-Manager link
App Logic App Logic
Tungsten Connector Tungsten Connector
Monitoring and control
Monitoring and control
Manager Manager Manager
Replicator Replicator Replicator
Slave Master Slave
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13. Node Failure
“Pause” incoming connection requests
+
Planned switch: Unplanned Failover:
wait for disconnect break connections
+
Transparent retry (autocommit tx only)
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14. Demo?
u1 u3
u2 u4
europe asia
world
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15. Installation
• tools/tpm con!gure <data service name>
<options>
--dataservice-connectors=node1,node2,...
• --connector-listen-port
--connector-user
--connector-password
--connector-smartscale=true
• tools/tpm help con!gure
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16. Specifying Users
• --connector-user=user1
• additional users in
tungsten-connector/conf/user.map
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17. user map
<user> <password> <data service> [<preferred site>]
tungsten_testing private world europe
myuser p4$$ asia
alice - othersvc
No need to restart
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18. Connection Protocol
version #, ..., salt
App Database, user,
Salted password
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19. A Man in the Middle
Connector
App
?
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20. Clear text passwords
• Workaround:
@script /opt/continuent/share/gen_user_map.sh
• output identical to regular user.map
• Can be any script: SQL requests, encrypting, etc.
• Accepts parameters
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21. Application con!guration
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22. Application con!guration - PHP
<?php
$host = “u1”;
$port = 9999;
$username = “tungsten_testing”;
$password = “secret_private”;
$dbname = “myapp";
$connection = mysqli_connect($host, $username,
$password, $dbname, $port);
......... More application logic here .........
?>
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23. Application con!guration - Java
• Hibernate
hibernate.connection.url=jdbc:mysql://u1:9999/mydb
• JBoss
<connection-url>jdbc:mysql://u1:9999/database</
connection-url>
• JDBC
jdbc:mysql://u1:9999/dbname
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24. Application con!guration - Ruby on
Rails
prod:
adapter: mysql2
encoding: utf8
database: my_db_name
username: tungsten_testing
password: private
host: u1
port: 9999
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25. Read/write splitting
• Automatic
• Application Controlled
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26. Automatic R/W splitting
• No application changes
• Only outside transaction boundaries
• 2 variants:
• Smart Scale
• @direct connections
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27. Automatic R/W splitting - smartScale
• AKA ‘session consistency’ QoS
• Ability to see session’s writes
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28. SmartScale
Master Transaction
DBMS History Log
write
Session x
App Session y
...
Slave
replay
Connector position
Slave
DBMS
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29. SmartScale
Master Transaction
DBMS History Log
read
Session x
App
Connector Slave
replay
position
Slave
DBMS
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30. SmartScale
Master Transaction
DBMS History Log
read
Session x
App
Connector Slave
replay
position
Slave
DBMS
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31. SmartScale
• Enabling:
tpm configure <data service name>
<other options>
--connector-smartscale=true
--connector-smartscale-sessionid=
DATABASE |
USER |
CONNECTION |
PROVIDED_IN_DBNAME
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32. SmartScale
• Choose you sessionId:
• PROVIDED_IN_DBNAME (++)
=> set dbname to ”mydb?sessionId=12345”
• CONNECTION (+)
• USER (-)
• DATABASE (--)
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33. Demo?
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34. SmartScale
Limitations:
• single connector instance
• select function_that_writes();
• ephemeral SQL objects
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35. SmartScale
Trade-o":
• Can read outdated data from other sessions
• Poor e!ciency in write intensive environments
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36. Automatic R/W splitting - directReads
• Blind R/W splitting
• Fast
• Similar limitations:
• ephemeral SQL objects
• select function_that_writes();
• Reads potentially outdated data
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37. DirectReads
• Enabling
tpm configure <ds> <opts>
--connector-rwsplitting=true
• Other users in user.map
@direct user2
@direct user3
• Can be backed by a c3p0 pool
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38. Read/write splitting
• Automatic
• Application Controlled
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39. Application-driven R/W splitting
• More e#cient...
• ...but potentially dangerous
• 3 possibilities:
• SQL comments
• QoS in database name
• @hostoption
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40. Selective R/W Splitting
• Must enable directReads
tpm update ...
--connector-rwsplitting=true
--property=selective.rwsplitting=true
• Embedded SQL comment:
!!! mysql -u... -c
/* TUNGSTEN_URL_PROPERTY=qos=RO_RELAXED */select @@hostname;
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41. Demo?
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42. QoS at connection time
• No connector con!guration change
• connect to “mydb@qos=RO_RELAXED”
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43. Demo?
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44. Host-based routing
• /etc/hosts
127.0.0.1 master.localhost
127.0.0.2 slave.localhost
• tpm configure <data service name> <other options>
--connector-rw-addresses=master.localhost
--connector-ro-addresses=slave.localhost
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45. Demo?
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46. SOR (multi site)
• Getting a local slave
<user> <password> <data service> [<preferred site>]
tungsten_testing private world europe
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47. Demo?
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48. Performance
• Pool for DirectReads
tpm configure <ds> <opts>
--connector-rwsplitting=true
--property=directReadsUsePool=true
•
JDBC driver
--property=jdbc.driver.options=
cacheServerCon!guration=true&characterSetResults=UTF8
https://docs.continuent.com/wiki/display/
TEDOC/Improving+Connection+Speed
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49. Getting connector information
• “tungsten connection status” for last request
mysql> tungsten connection status;
+---------------------------------------------------------------+
| message |
+---------------------------------------------------------------+
| internal(OPEN) DIRECT TO u1@default(master:ONLINE) STATUS(OK) |
+---------------------------------------------------------------+
1 row in set (0.01 sec)
• “tungsten show processlist” for real client
addresses
mysql> tungsten show processlist;
+------------+------+----------+-----------+----------+---------+------+-------+------+
| DataSource | Id | User | Host | db | Command | Time | State | Info |
+------------+------+----------+-----------+----------+---------+------+-------+------+
| u1 | 1342 | tungsten | mac:64477 | tungsten | Sleep | 20 | | NULL |
+------------+------+----------+-----------+----------+---------+------+-------+------+
1 row in set (0.13 sec)
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50. Troubleshooting
• tungsten-connector/log/connector.log
• Lots of connections in TIME_WAIT state
• Too many open !les
• OutOfMemory error
• New connections hanging
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51. Tungsten University Sessions
• Manage multi-master or fan-in replication
topologies - March 7th & 12th
• Zero-downtime maintenance and schema
operations - March 21st & 26th
• Geographically distributed MySQL clusters -
April 11th & 16th
• Replicate between MySQL and Oracle -
May 2nd & 7th
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52. 560 S. Winchester Blvd., Suite 500 Our Blogs:
San Jose, CA 95128 http://scale-out-blog.blogspot.com
Tel +1 (866) 998-3642 http://datacharmer.org/blog
Fax +1 (408) 668-1009 http://www.continuent.com/news/blogs
e-mail: sales@continuent.com
Continuent Web Page:
http://www.continuent.com
Tungsten Replicator 2.0:
http://code.google.com/p/tungsten-replicator
©Continuent 2013