MySQL performance optimisation talk, performed in Rotterdam on PHP meetup! Performed by Dimitri Vanoverbeke (Percona)

1. Dim0 (Dimitri Vanoverbeke)
PHP Meetup Rotterdam
November 12th 2015
Practical MySQL Performance
Optimization

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Who am I?
• Linux system engineer
and Consultant for 8
years
• Solution Engineer @
Percona
• www.twitter.com/dim0
2

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Contents of the presentation
How do we approach performance
optimisations
Discuss practical optimisation tips.
What tools exist?

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MySQL performance
MySQL
Performance
does not
Matter

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What matters?
My Website/
App is
important

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Things to Note
Performance issues can
be unrelated to MySQL
Maybe the solution is not MySQL

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Many other tools
Cassandra
MongoDB
Hadoop
ElasticSearch
Redis

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Putting it in Practice
Keep an unbiased view
Focus on the Stack

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Performance “sandbags”
Security
Manageability
Compatibility
Compliance
Ease of use by developers

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“Good Enough”
KNOW
WHEN TO
STOP

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So what is important in
MySQL?
Queries!!!!
• Inserts
• Selects
• Updates
• Deletes

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What are we aiming for?
Quickly, Efficiently,
Reliably…

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Quickly
Good Response Time
For all Users and Use
Cases

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Efficiency
Resources
CPU, Memory, IO, Disk Space
Euro’s
Human Effort

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Reliably
High Availability!
High Availability and
Performance Come together

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Consider things
• But avoid focus on extreme
outliers
Look beyond
averages
• Daily and Weekly cycle
• Growth of load and Data Size
Make sure to
look at trends
over time
• Data size changes?
Think about the
Future

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Schema
Look at the
Schema
and queries
together
• Minor Schema changes
• Data Architecture

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Schema Tips
Learn indexing
• http://bit.ly/1rAtamE
Design Schema for Data access
• Rethink your schema
Technical voodoo
• Partitioning and Sharding
• Normalization and denormalization

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The following also Matters
Infrastructure
• Storage systems, virtualization, etc.
Operating system and configuration
• Disk scheduler, FS, etc…
MySQL Version
• Are you using Percona Server, MariaDB, MySQL?
MySQL configuration
• The default configuration of Hell…

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Optimization Process
Low Hanging
Fruit
• MySQL
Configuration
• OS settings
• Indexes
• Caching
Medium Level
• InfraStructure
• MySQL
Version
Hard Changes
• Major schema
changes
• Application
architecture
changes

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QUICK TIPS

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Hardware
CPU
Memory
Disk
Network

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OS choices are simple
Linux
Server Grade
Recent
Well supporting MySQL

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OS tuning
Defaults are good for Common workload
Filesystem: EXT4 or XFS
More details: http://bit.ly/MySQLonLinux
Well supporting MySQL

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MySQL Version
New versions typically improve performance
Scalability, improved optimizer
Expect some regression
Try maybe a different flavor? Percona Server 5.6

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MySQL config optimisations
Do NOT run with defaults
Do not ever obsess with tuning
More details: http://bit.ly/1vth5Cu

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MySQL tuning in 1 slide
• max_connections
• log_bin
• open_files_limit
• innodb_buffer_pool_size
• innodb_log_file_size
• innodb_flush_log_at_trx_commit
• innodb_flush_method=O_DIRECT

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TOOLS

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Tools to Consider
• pt-query-digest (Percona Toolkit)
• Other Percona-toolkit tools
• Percona Monitoring plugins
• MySQL Enterprise Monitor
• Monyog
• VividCortex
• New Relic

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Percona toolkit helps
Identify Manage
Understand Monitor
Percona
Toolkit

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What is Percona Toolkit?
• Collection of command-line tools for a wide range of MySQL
DBA tasks
• Works with MySQL 5.0+, MariaDB, Percona Server, Percona
XtraDB Cluster
• Professionally developed, supported, and maintained by
Percona
• 7 years maturity, thousands of tests, 20 testing environments, 1
full-time developer
• Free, open-source www.percona.com/software/percona-toolkit
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Installation
• Rpm and deb packages are available
http://www.percona.com/downloads/percona-toolkit /LATEST/
• Or you can use a tarball
wget percona.com/get/percona-toolkit.tgz
• Extract, then make, make install
Or, if you only need a specific tool
wget percona.com/get/TOOL
2

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pt-query-digest
Command Line tool from Percona Toolkit
Process Logs Manualy
Powerful Filtering
Storing History

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pt-query-digest example

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Top Queries

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Query Details

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More Query Details

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Where to Analyze ?
• Development to catch
bad queries early
• Production to catch
good queries starting
to go bad
Both !

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Query Performance can show
modifying parameters
Workload Changes
Data Size
Changing Query Plans
Upgrading MySQL Version
Changing MySQL Settings
Hardware Changes

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But Why Slow ?
• MySQL Level
• OS Level
• Hardware/
Environment Level
Need to
know more
than query
level
information

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Hardware visibility
Eeek!
I have a
new
machine
What are the specs?
What is the current memory usage?
How is the storage system currently set up?
What are the OS specifics that are currently
applied?

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Lack of visibility

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pt-summary
[ec2-user@ip-172-31-0-249 ~]$ pt-summary
# Percona Toolkit System Summary Report ######################
Date | 2015-08-31 11:20:01 UTC (local TZ: UTC +0000)
Hostname | ip-172-31-0-249
Uptime | 14 days, 23 min, 1 user, load average: 0.00, 0.01, 0.05
Platform | Linux
Release | Amazon Linux AMI release 2015.03
Kernel | 3.14.35-28.38.amzn1.x86_64
Architecture | CPU = 64-bit, OS = 64-bit
Threading | NPTL 2.17
SELinux | No SELinux detected
Virtualized | Xen

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Continue pt-summary
# Processor ##################################################
Processors | physical = 1, cores = 2, virtual = 2, hyperthreading = no
Speeds | 2x2494.026
Models | 2xIntel(R) Xeon(R) CPU E5-2670 v2 @ 2.50GHz
Caches | 2x25600 KB
# Memory #####################################################
Total | 3.9G
Free | 1.9G
Used | physical = 2.0G, swap allocated = 0.0, swap used = 0.0, virtual = 2.0G
Buffers | 147.4M
Caches | 1.6G
Dirty | 52 kB
UsedRSS | 134.3M
Swappiness | 60
DirtyPolicy | 20, 10
DirtyStatus | 0, 0

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Continue pt-summary (2)

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Continue pt-summary (3)

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pt-mysql-summary
MySQL visibility

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Continue pt-mysql-summary

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Continue pt-mysql-
summary(2)

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Continue pt-mysql-
summary(3)

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Pt-stalk
• You are having performance problems, however it’s difficult to pinpoint
what is causing it.
• Analyse Data
• Fix what is wrong
• Problems can occur randomly
• Problems can happen while you are not monitoring
• pt-stalk is a tool which gives you the ability to monitor variables while
you are not keeping an eye on them

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Continue pt-stalk

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Innotop
Innotop
• Identify
• Understand
• Monitor

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Innotop
• Sometimes it’s hard to keep track of the
active queries on your system.
• Amount of queries are confusing
• Which query should I explain
• Which query is problematic?
• Why, how, where, what?

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Innotop: Enter innotop
• It’s like top, but for queries
5
5

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Innotop: Innodb I/O
information
5
6

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Innotop: Variables overview
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7

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FINAL WORDS

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Dim0
Dimitri.vanoverbeke@percona.com
Thank You!