MaxScale - The Pluggable Router by Anders Karlsson, SkySQL Presented 24.6.2014 at the MariaDB Roadshow in Maarssen, The Netherlands.

1. © SkySQL Corporation Ab. Company Confidential.
MaxScale – The Pluggable Router
Anders Karlsson
Senior Sales Engineer, SkySQL

2. © SkySQL Corporation Ab. Company Confidential.
Agenda
• What is MaxScale and why do we need it?
• MaxScale Design
• MaxScale modules
• MaxScale use cases
• Demo

3. © SkySQL Corporation Ab. Company Confidential.
Scaling beyond a single server
• Scaling with a single server is expensive
• A single large server is more expensive than
many small ones
• A single large server is more vulnerable than
many small ones
• Scaling across many small servers can be
difficult though
• A Load Balancer works but doesn’t know about
MariaDB/MySQL traffic

4. © SkySQL Corporation Ab. Company Confidential.
Why do we need MaxScale
• We need something better and different than
just a Load Balancer
• We need something that knows about MariaDB
traffic
• We need something fast and flexible, yet
lightweight

5. © SkySQL Corporation Ab. Company Confidential.
We need a scale out server
• A server that scales out the load to other
servers
• A server that is transparent to applications and
servers
• A server that can parse SQL requests and act
accordingly depending on the content

6. © SkySQL Corporation Ab. Company Confidential.
MaxScale Objectives
•Highly scalable
•Transparent to the application
•Highly available
•Extendible
•Flexible
•Modules define MaxScale functionality
•Open source, GPL2 software
since 8th of Jan. 2014

7. © SkySQL Corporation Ab. Company Confidential.
Implementation details
• Mostly written in C (with a little C++) (thank you!)
• Multi-threaded
• epoll() based mechanism
• Dynamic configuration and reconfiguration
supported
• State of servers determined dynamically
• Multiple setup in allowed in a single MaxScale
setup

8. © SkySQL Corporation Ab. Company Confidential.
MaxScale modules
Core of MaxScale is multi-threaded, event-driven network IO processor
10/06/2014
Client authenticates
once - with MaxScale
Alter, block or log client
requests and results
Content-aware or unaware routers
Configuration and state
aware monitors
Allows multiple protocols for
clients and servers

9. © SkySQL Corporation Ab. Company Confidential.
Protocol modules
• Implements a protocol that can access
MaxScale
• MySQL / MariaDB Client and server supported
• http and telnet for monitoring, configuration and
debugging

10. © SkySQL Corporation Ab. Company Confidential.
Authentication modules
• Authenticates clients
• Based on data from connected servers
• MaxScale does not in and of itself have an
authentication / user database, this is picked up
from connected servers

11. © SkySQL Corporation Ab. Company Confidential.
Monitor modules
• Monitors the state of connected servers
• Used to provide information for routing modules
• Currently monitors MySQL / MariaDB and
Galera Clusters

12. © SkySQL Corporation Ab. Company Confidential.
Router modules
• Router traffic from clients to servers, using a
specified rule
• Two router modules are currently available
• Connection routing
• Read / Write split
• This is the most important type of
module

13. © SkySQL Corporation Ab. Company Confidential.
Filter modules
• Optional type of module
• Allows filtering and processing of SQL
statements and results
• Simple regex filter available with MaxScale 0.7
• Queries may be inspected, modified or rejected
• Multiple filters may be chained

14. © MariaDB. Company Confidential.
Read Scalability with MySQL Replication
using MaxScale Connection Load Balancing
ClientClient Client For applications that need read scalability and load
balancing and can use separate connections for
reads and writes.
Each client establishes one
connection for writes and one for
reads
Master Slave Slave
[write service]
type=service
router=readconnroute
router_options=master
servers=s1,s2,s3,..,sn
[read service]
type=service
router=readconnroute
router_options=slave
servers=s1,s2,s3,..,sn
Slave Slave
...

15. © MariaDB. Company Confidential.
Consistent Read Scalability with Galera
using MaxScale’s Read/Write Split Router
ClientClient Client For applications that require read scalability with
consistent reads and High Availability with fast
failovers.
MaxScale selects one as
a master and one or more cluster
members to slave(s)
If node fails a new master can
be chosen immediately.

16. © MariaDB. Company Confidential.
Query rewrite and filtering
by using MaxScale’s filters
ClientClient Client
For applications with multiple different
backend databases. For database firewalling,
etc.
CREATE TABLE
SUPPLIER(ID INTEGER,
NAME VARCHAR)
TYPE=INNODB
[regex]
type=filter
module=regexfilter
match=TYPE
replace=ENGINE
CREATE TABLE
SUPPLIER(ID INTEGER,
NAME VARCHAR)
ENGINE=INNODB

17. © MariaDB. Company Confidential.
Query rewrite and filtering (cont.)
by using MaxScale’s filters
ClientClient Client
For sloppy administrators :-)
Select count(*) f0rm
mysql.user
[regex]
type=filter
module=regexfilter
match=[Ff][Oo0][Rr][Mm]
replace=FROM
Select count(*) FROM
mysql.user

18. © MariaDB. Company Confidential.
Basic Setup
● Clients access MaxScale
● MaxScale in the app server,
UNIX sockets
● Database servers accessed
via TCP
● Clients
● Application Server
Database Cluster

19. © MariaDB. Company Confidential.
Typical Scenarios
● MySQL Replication with
● Read connection load
balancing
● Read/Write statement
splitting
● Galera Cluster
● Connection load balancing
● Read/Write statement
splitting
● Write conflict avoidance
(planned)

20. © MariaDB. Company Confidential.
Inside MaxScale
MySQL Local Authentication
Backends Clients
ok
“read user, host” connect/auth
Users are loaded at start

21. © MariaDB. Company Confidential.
Inside MaxScale
Read/write splitting
“call my_proc(1)”
Master
Slave
Query Classifier

22. © MariaDB. Company Confidential.
Inside MaxScale Routing

23. © MariaDB. Company Confidential.
Inside MaxScale Routing

24. © MariaDB. Company Confidential.
What’s new in R/W split router
● Session Commands
● Local variables, User change,
SET auto commit
● Execute in master & slave but
maintain execution order
● Current limitation : queries not
supported in session
commands
SET @a=(SELECT COUNT(*) FROM mysql.user)
is executed in both nodes.
● Galera H/A Support
● Fault Tolerance
● Replication consistency
● Transaction support
● Within active transaction
everything is routed to master
● Detection of implicit BEGIN and
ROLLBACK/COMMIT

25. © MariaDB. Company Confidential.
MaxScale 0.7
●Galera support
○Read/Write Split router for Galera Cluster
●Multiple slaves support
○Read/Write Split router allows multiple
slave connections
●Debug Interface enhancements
○Support for wide variety of MaxScale
objects
○User mode support

26. © MariaDB. Company Confidential.
MaxScale 0.7
●Maintenance mode for servers
●Configurable monitoring interval
●Replication Lag Heartbeat Monitor
●Filter Modules support
●MariaDB 10 Replication
support

27. © MariaDB. Company Confidential.
Demo scenarios
● 1 Master
● 2 Slaves

28. © MariaDB. Company Confidential.
Get involved
● Check on GitHub https://github.com/skysql/MaxScale
● MariaDB Source https://downloads.mariadb.org/
● Bugs report
http://bugs.skysql.com/buglist.cgi?product=Maxscale
● Google groups
https://groups.google.com/forum/#!forum/maxscale
● Binary Tarball
http://downloads.skysql.com/files/SkySQL/MaxScale
● SkySQL website http://www.skysql.com

29. © MariaDB. Company Confidential.
MaxScale - Thank you!