Scaling 101
A Brief Overview
Leonard Lin
Elgg Camp Boston 2009

See Also
• http://www.iamcal.com/talks
• http://develooper.com/talks

FE Performance
90%
http://developer.yahoo.com/
performance/
http://code.google.com/speed/
articles/
http://www.slideshare.net/souders
http://www.slideshare.net/stoyan

+1

SPOF

Architecture
vs.
Plumbing

Let’s Grow A
LAMP Site

O HAI.
Apache
PHP
MySQL

NO PROBLEMO.
Apache
PHP
MySQL

WIN!
CDN

BOO-URNS.
CDN

Internet Scale
• Millions of Users
• 1000’s QPS
• Spiky Traffic
• (Pretty) High Availability
• Ability to Keep Growing

Know Your Limits
• Can you tell me how many QPS
you can handle right now?
• How long until you hit capacity?
• Etc...

Instrument anything
that moves.
(but do it right)

Capacity Planning
http://kitchensoap.com/
http://www.slideshare.net/jallspaw/

Start with 2

Stolen from Cal

Subsystems
• Independent (remove SPOF)
• Make overly large datasets
manageable
• Simplify performance profiles

Transactional
vs.
Everything Else

How Real-Time is
Real-Time?
http://decafbad.com/
blog/2008/07/04/
queue-everything-and-
delight-everyone
http://
laughingmeme.org/
2008/07/07/a-couple-
of-caveats-on-queuing/

You have a
Database. Now
don’t touch it.

Cache-Until-
Invalidate

http://www.mysqlperformanceblog.com/
http://conferences.percona.com/
percona-performance-conference-2009/
schedule.html
http://www.maatkit.org/
http://blog.mysqltuner.com/
http://mysqltuner.pl/mysqltuner.pl
http://www.day32.com/MySQL/

• Replication
• Multi-master
• Functional Partitioning
• Federation / Sharding

Transactional DB
• InnoDB Only
• 1s Slow Log (or Percona patch)
• No (Big) Joins
• No Temp Tables

Why Simple Queries?
+-------------------------------+-----------+
| Variable_name | Value |
+-------------------------------+-----------+
| Innodb_row_lock_time | 131938036 |
| Innodb_row_lock_time_avg | 25951 |
| Innodb_row_lock_time_max | 51974 |
| Innodb_row_lock_waits | 5084 |
| Table_locks_immediate | 198815316 |
| Table_locks_waited | 645178 |
+-------------------------------+-----------+

On Performance
• SQL_NO_CACHE
• Cardinality of Indexes
• Ranged Indexes
• EXPLAIN
• COUNT(*)

On Performance
• Float vs Decimal
• CHAR vs VARCHAR vs TEXT
• INT vs STRING
• LIKE(‘blah%’) vs LIKE(‘%blah%)

MySQL is a hammer,
but not everything is
a nail.

Queues

Inverse Indexes
(aka Search)

Geospatial Indexes

Graph Engines

Recommendations

Distributed
Systems

Text
http://www.allthingsdistributed.com/
2007/10/amazons_dynamo.html

Q&A