© Continuent 2009
Database PerformanceDatabase Performancewith Proxy Architectureswith Proxy Architectures
TungstenTungsten SQL RouterSQL Router
Robert Hodges
CTO, Continuent, Inc.
Percona Percona Performance Is Everything 2009Performance Is Everything 2009
© Continuent 2009
The “Proxy Math” Problem
/ Proxy layers solve a number of database problems• Seamless failover• Intelligent load balancing• Intelligent partitioning
/ Big Question: What’s the cost for applications?
/ Let’s run a few tests to show basic limits• Simple queries with data guaranteed to be in buffer cache• Dell SC 1425, Xeon 2 CPU x 2 Cores, 2.8Mhz• No/minimal proxy logic
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Proxy Overhead Compared to Databases
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Proxy with Increasing Result Sizes
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How Do We Avoid Proxy Math?
/ Proxy performance is CPU intensive• Mostly copying and transforming bytes
/ Bad case: 4x CPU resources for same throughput• Could be far worse if proxy does more than copy data• It’s not enough to make proxies faster
/ Alternative 1: Hardware load balancer• If I only had a brain…
/ Alternative 2: VIPs• Handy for availability but load balancing is a problem
/ Alternative 3: An embeddable library• This would work on Amazon as well!
© Continuent 2009
Tungsten SQL Router Overview
/ Library-based intelligent failover and load balancing
/ Connection-level routing
/ Implemented as JDBC library wrapper (Java!)• Adds intelligence to vendor drivers
/ DBMS-independent and non-partisan
/ 100% open source• http://sourceforge.net/projects/tungsten
/ Built-in management• Manageable from network• Monitoring integration
/ Routing based on CAP theorem• Trade off consistency vs. availability vs. partition tolerance
© Continuent 2009
CAP-Based Routing--“Quality of Service”
Connection for WritesConnection for Writes
jdbcjdbc::t-routert-router://mysvc/db1://mysvc/db1??qos=RW_STRICTqos=RW_STRICT
Connection for ReadsConnection for Reads
jdbcjdbc::t-routert-router://mysvc/db1://mysvc/db1??qos=RO_RELAXEDqos=RO_RELAXED
SessionSessionConsistency*Consistency*
StrictStrictConsistencyConsistency
RelaxedRelaxedConsistencyConsistency
MasterMaster SlaveSlaveSlaveSlave
SlaveSlave
ReplicationReplication
(latency)(latency)
*In progress*In progress
(Data Service)(Data Service)
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Services and Data Sources
/ SQL Router connects to services, not hosts
/ Services are composed of data sources
/ Configuration stored in CLUSTER_HOME directory
/ Configuration updated by administrative commands
$CLUSTER_HOME/$CLUSTER_HOME/services/services/
mysvc/mysvc/datasource/datasource/
db1.propertiesdb1.propertiesdb2.propertiesdb2.propertiesdb3.propertiesdb3.properties
replicator/replicator/
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Administration and Monitoring
/ SQL Router library has JMX ports for administration
/ Update status of data sources using rmctl program:
sql-router[mysvc:ONLINE]> db2 offline
SENT NOTIFICATION: DATASTORE db2 offline
sql-router[mysvc:ONLINE]> db1 online
SENT NOTIFICATION: DATASTORE db1 online
sql-router[mysvc:ONLINE]> db3 online
SENT NOTIFICATION: DATASTORE db3 online
/ Listeners for monitoring events• Use UDP or group communications or…• Automatically take data sources online/offline
© Continuent 2009
Does It Work with Non-Java Programs?
/ Yes
/ Use Tungsten Connector as front end
/ Full circle back to better SQL proxies
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Tungsten Drilldown Tungsten Drilldown –– SQL-Router SQL-Router
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Roadmap
/ Upgraded monitoring• Create/remove data sources automatically from monitoring data• Specify maximum permitted latency
/ Session consistency
/ Partitioning / Sharding• Route databases to different servers
© Continuent 2009
HQ and Americas560 S. Winchester Blvd., Suite 500
San Jose, CA 95128
Tel (866) 998-3642
Fax (408) 668-1009
My e-mail: robert.hodges “at” continuent.com
EMEA and APACLars Sonckin kaari 16
02600 Espoo, Finland
Tel +358 50 517 9059
Fax +358 9 863 0060
Contact InformationContact Information
Commercial solutions:http://www.continuent.com
Tungsten open source stack:http://community.continuent.com
http://sourceforge.net/projects/tungsten
