Download - Tungsten University: Unleashing the Power of Tungsten Connectors

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Tungsten University:Unleashing the Power of

Tungsten ConnectorsGilles Rayrat, Director of Operations/France

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What is Tungsten Connector?

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Connector

App

NativeprotocolCOM_QUERY

COM_INIT_DBCOM_DROP_DB

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A Key Tungsten Component

3

• Provide access to the master

• Handle database failures

• Can access slaves for reads

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Deployments

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Deployment 1: app servers

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App Server+ Connector





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Deployment 2: database servers

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Software Load Balancer

...

App Server App Server App Server App Server App Server App Server

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Deployment 3: dedicated hosts

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...

Hardware Load Balancer

App Server App Server App Server App Server App Server App Server

...

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Deployment best practice

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Install with port 3306!

tools/tpm con!gure <data service name>

<options>

--connector-listen-port=3306

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Closer view

• Performance

• Failure handling

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Packet Streaming

• Fast operations, Low overhead

• Full transparency

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Connector

App

Protocol packetCOM_QUERY

select * from t

Protocol packetOK

ResultSet Rows:1

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Closer view

• Performance

• Failure handling

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Connector-Manager link

Master Slave

App Logic

Tungsten Connector

Replicator Replicator Replicator

App Logic

Tungsten Connector

Manager Manager Manager

Monitoring and control

Monitoring and control

Slave

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Node Failure

“Pause” incoming connection requests+

+

Transparent retry (autocommit tx only)

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Planned switch:wait for disconnect

Unplanned Failover:break connections

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Demo?

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asia

worldeurope

u1

u2

u3

u4


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


Specifying Users

• --connector-user=user1

• additional users in

tungsten-connector/conf/user.map


user map

<user> <password> <data service> [<preferred site>]

tungsten_testing private world europemyuser p4$$ asiaalice - othersvc

No need to restart


Connection Protocol

App

version #, ..., salt

Database, user,Salted password


A Man in the Middle

App

Connector

?


• 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

Clear text passwords

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Application con!guration

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Application con!guration - PHP

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<?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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Application con!guration - Java

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• 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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Application con!guration - Ruby on Rails

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prod:

adapter: mysql2

encoding: utf8

database: my_db_name

username: tungsten_testing

password: private

host: u1

port: 9999

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Read/write splitting

• Automatic

• Application Controlled

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Automatic R/W splitting

• No application changes

• Only outside transaction boundaries

• 2 variants:

• Smart Scale

• @direct connections

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Automatic R/W splitting - smartScale

• AKA ‘session consistency’ QoS

• Ability to see session’s writes

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SmartScale

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App

Connector

MasterDBMS

TransactionHistory Log

SlaveDBMS

Slavereplay

position

write

Session xSession y...


SmartScale

App

Connector

MasterDBMS


SlaveDBMS

Slavereplay

position

read

Session x


• Enabling:

tpm configure <data service name> <other options> --connector-smartscale=true --connector-smartscale-sessionid= DATABASE | USER | CONNECTION | PROVIDED_IN_DBNAME

SmartScale


• Choose you sessionId:

• PROVIDED_IN_DBNAME (++)=> set dbname to ”mydb?sessionId=12345”

• CONNECTION (+)

• USER (-)

• DATABASE (--)

SmartScale

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Demo?

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Limitations:

• single connector instance

• select function_that_writes();

• ephemeral SQL objects

SmartScale


Trade-o":

• Can read outdated data from other sessions

• Poor e!ciency in write intensive environments

SmartScale

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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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DirectReads

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• Enablingtpm configure <ds> <opts> --connector-rwsplitting=true

• Other users in user.map@direct user2@direct user3

• Can be backed by a c3p0 pool


Application-driven R/W splitting

• More e#cient...

• ...but potentially dangerous

• 3 possibilities:

• SQL comments

• QoS in database name

• @hostoption

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Selective R/W Splitting

• Must enable directReads

tpm update ...--connector-rwsplitting=true \--property=selective.rwsplitting=true

• Embedded SQL comment:

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!!! mysql -u... -c

/* TUNGSTEN_URL_PROPERTY=qos=RO_RELAXED */select @@hostname;

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Host-based routing

• /etc/hosts127.0.0.1 master.localhost127.0.0.2 slave.localhost

• tpm configure <data service name> <other options> --connector-rw-addresses=master.localhost --connector-ro-addresses=slave.localhost

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SOR (multi site)

• Getting a local slave

<user> <password> <data service> [<preferred site>]

tungsten_testing private world europe


Performance

• Pool for DirectReads

tpm configure <ds> <opts> --connector-rwsplitting=true --property=directReadsUsePool=true

• JDBC driver

https://docs.continuent.com/wiki/display/TEDOC/Improving+Connection+Speed

--property=jdbc.driver.options=

cacheServerCon!guration=true\&characterSetResults=UTF8

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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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Tungsten University Sessions

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• 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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Continuent Web Page:http://www.continuent.com

Tungsten Replicator 2.0:http://code.google.com/p/tungsten-replicator

Our Blogs:http://scale-out-blog.blogspot.comhttp://datacharmer.org/bloghttp://www.continuent.com/news/blogs

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