MaxScale - The Pluggable Router by Serge Frezefond. Presented 26.6.2014 at the MariaDB Roadshow in Paris, France.

1. © SkySQL Corporation Ab. Company Confidential.
MaxScale – The Pluggable Router
Serge Frezefond,
Cloud Solution Architect, SkySQL

2. © SkySQL Corporation Ab. Company Confidential.
MaxScale Objectives
• Highly scalable
• Transparent to the application
• Highly available
• Extendible
• Flexible
• Modules specify what MaxScale is :
router / firewall / data extract tool /…
• Open source, GPL2 software since 8th
of Jan. 2014

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How? In a nut shell
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

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Read Scalability with MySQL Replication
using MaxScale’s 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
...

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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.

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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

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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

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MaxScale 0.7
● Galera support
○ Read/Write Split router for Galera Cluster
● Multiple slaves support
○ Read/Write Split router allows multiple slave connections and balancing load between them
● Debug Interface enhancements
○ Support for wide variety of MaxScale objects which can be referenced by their names instead of memory
addresses
○ User mode to prevent access by using memory addresses
● Maintenance mode for servers
● Configurable monitoring interval
● Replication Lag Heartbeat Monitor
● Filters API
● MariaDB 10 Replication support in MySQL monitor
Release notes: https://github.com/skysql/MaxScale/blob/release-
0.7/Documentation/Debug%20And%20Diagnostic%20Support.pdf

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Basic Setup
● Clients access MaxScale
● MaxScale in the app server,
UNIX sockets
● Database servers accessed
via TCP
● Clients
● Application Server
Database Cluster

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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)

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Inside MaxScale
MySQL Local Authentication
Backends Clients
ok
“read user, host” connect/auth
Users are loaded at start

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Inside MaxScale
Read/write splitting
“call my_proc(1)”
Master
Slave
Query Classifier

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Inside MaxScale Routing

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Inside MaxScale Routing

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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

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What’s coming
● Filters
● Routing hints
● Multiple Slave Support
● Weight based routing
● Backend failure tolerance
● Enforce Node Replication consistency for
MariaDB 10 & MySQL 5.6

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Extending with filters
● May be connected to form arbitrary chains
● Allows inspection, modification and rejection of requests and results
● blacklist
● data mining / log

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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

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MaxScale - Thank you!