Top5 scalabilityissues

The Top 5
Things You
are doing
today to
hinder
scalability
Dan Wilson

Who is Dan
Wilson
 Runs ChallengeWave.com,
Datacurl LLC and NCDevCon
 Owner of Model-Glue
 Dad of 2, Husband to 1
 Loves all things technical
and a good debate
Gives bad stock tips

Our Top 5 List
1.Monolithic Design
2.Mis-identification/Misuse of shared
resources
3.Over-reliance on Shared Scopes
4.Stupid Developer Tricks
5.Failure to design for cacheability

Monolithic Design
Credit: http://thecodelesscode.com/case/33

Solution: Decouple Functionality

Cost of WebServer File
Web Server Thread
+ Network to File System
+ Disk Wait Time
+ Disk Seek Time
+ Transfer time to Webserver
+ Transfer time to complete HTTP Request
______________________
Total Time

Cost of 1 ColdFusion File
Web Server Cost
+ Network Cost to CF Server
+ CF Parsing or Classloading Time
+ Thread Wait time
+ Thread CPU time
+ Transfer time for CF buffer to Webserver
______________________
Total Time

Cost of ColdFusion File With Query
Web Server Cost
+ ColdFusion File Cost
+ Number of Queries ( Network time to DB + Query
Execution Plan + Query Execution + Disk Wait + Disk Seek )
+ Network time to transport result set to CF
+ CF Parsing Time
______________________
Total Time

Types of Shared Resources
● Memory, CPU, Disk Space
● Disk Transfer (Databases!!)
● JVM Space
● ColdFusion template cache
● ColdFusion Threads
● Network Traffic
● Database/Data Store
● Blah
● Blah
● Blah

Over-reliance on Shared Scopes
● Session Scope use is the largest culprit
● Sometimes you have to deoptimize a few
operations in order to provide a scalable
solution (like stop caching a state query in application
scope)
● If you want to use a shared scope and want to
keep an eye on scalability later, use a lookup
factory.

But, what about sticky sessions?

Make the Key
<cfset UserToken = “#UserID#|” />
<cfset UserToken = UserToken & “MySharedSecret|” />
<cfset UserToken = UserToken & “#Email#|” />
<cfset UserToken = UserToken & “#DateFormat(now(),
“yyyymmdd”)# #TimeFormat(now(), “HH:mm:ss”)#” />
<cfset EncryptedUserToken = Encrypt(UserToken,
encryptionKey, “AES”, “Hex”) />
Use the Key
<cfset DecryptedUserTokenList =
Decrypt(EncryptedUserToken, encryptionKey, “AES”,
“Hex”) />

Stupid Developer Tricks
● Looped Queries
● Lazy-Man Pagination
● ScheduledTask-o-rama
● Database Abuse

Problem: Query in Loop
<cfloop query="OldLastLogins">
<cfquery name="UpdateUsers" datasource="#datasource#">
UPDATE Users
SET Active = 0
WHERE UserID = #OldLastLogins.UserID#
</cfquery>
</cfloop>

Solution?: SQL IN Statement
UPDATE Users
SET Active = 0
WHERE UserID IN #ValueList(OldLastLogins, UserID)#
</cfquery>

Solution: Joins
UPDATE users
INNER JOIN lastlogin ON users.userID = lastlogin.userID
SET Active = 0
WHERE lastlogin < now()
</cfquery>

Problem: EntityToQuery
<cfscript>
EntityToQuery(
EntityLoad("Users",
{ Gender =arguments.genderID}
)
);
</cfscript>

Ouch, It hurts when I do that!

Get Poll Answers
<cfset PollAnswers = entityLoad("PollAnswers",
{
PollID=entPoll[1].getPollID()
}, "")>
<cfif (isArray(Poll) AND arrayLen(Poll) gt 0)
AND (isArray(PollOpt)
AND arrayLen(PollOpt) gt 0)
AND (isArray(PollAnswers)
AND arrayLen(PollAnswers) gt 0)>

Poll Net Result
JDBC
Recordcount: 87,923
Query Time: 14,290 ms
All that for an
ArrayLen() GT 0!

Effect of adding 1 Index to Production

What is the number one
cause of missing indexes in
production?

Cross Joining for Fun and Profit
INSERT INTO activity ( memberID, ActivityTypeID, ActivityDate,
UnitOfMeasure, MetricValue, Description)
(
SELECT m.memberID, a.ActivityTypeID,
Date_Add( '2014-12-31', INTERVAL -mod( RAND(3)*300, 300) DAY),
UnitOfMeasure, MetricValue, Description
FROM member m, activity a
WHERE a.elapsedtime IS NOT NULL
AND a.description IS NOT NULL
AND mod( mod(m.memberid, 2), mod( a.activityid, 5) ) = 1
AND m.communityid = 1
)

Problem: Lazy Man Pagination
<cfoutput query="GetParks"
startrow="#StartRow#"
maxrows="#MaxRows#">
#ParkName#
</cfoutput>

Solution: SQL
MySql, PostgreSQL: LIMIT, OFFSET
SQL Server: TOP, ORDER BY
ORACLE: WHERE rownum <= 10

Problem: No Encapsulation
<cfif qExists.idexists>
<cfquery name="qUpdate" datasource="#somedatasource#">
UPDATE tblKalendarCategories
SET CategoryName = '#form.CategoryName#',
CategoryTextColor = '#form.CategoryTextColor#'
WHERE CategoryID = #form.CategoryID#' />
</cfquery>
<cfelse>
<cfquery name="qCreate" datasource="#somedatasource#">
INSERT INTO tblKalendarCategories
( CategoryName, CategoryBGColor, CategoryTextColor )
VALUES
( '#form.CategoryName#', '#form.CategoryTextColor#')
</cfquery>
</cfif>

Solution: Encapsulate Data Access
DAO.read();
DAO.save();
DAO.delete();
DAO.create();
DAO.exists();
DAO.update();

Caching HTTP Responses
Request:
GET /index.html HTTP/1.1
Host: www.example.com
Response:
HTTP/1.1 200 OK
Date: Mon, 23 May 2005 22:38:34 GMT
Server: Apache/1.3.3.7 (Unix) (Red-
Hat/Linux)
Last-Modified: Wed, 08 Jan 2003
23:11:55 GMT
ETag: "3f80f-1b6-3e1cb03b"
Content-Type: text/html; charset=UTF-8
Content-Length: 131
Accept-Ranges: bytes
Connection: close

Designing for a CDN or Reverse
Proxy Cache
● Use HTTP verb “GET” for cacheable content
● Use Last-Modified and Etag headers properly
● Encapsulate code that changes content to
centralize cache purge activity
● Personalize with Cookies/Javascript
● Set up shadow DNS to bypass caching
● Use Javascript for interactions
● Design data for high cache hit ratios

NoSQL as a Cache
{
"_id" : ObjectId("51fff472e09a41ac19dd1876"),
"NAME" : "Dan",
"KIDS" : [
{
"NAME" : "Nick",
"AGE" : 3.5,
"DESCRIPTION" : "crazy",
"HAIR" : "blonde"
},
{
"NAME" : "Jack",
"AGE" : 1.75
}
]
}

Designing for a NoSQL Cache
● Encapsulate calls to NoSQL engine
● Encapsulate data publish methods
● Design Content Purge algorithms well
● Ensure the NoSQL engine is the authoritative
source for the data being stored

Designing for a Key Value Store
Cache
● Encapsulate data access calls so you can
purge/reload
● Avoid cffunction output=”true”
● Choose correct cache expiry strategy (time,
LRU)
● Easy to integrate with CF ORM
● Use to remove load hotspoting

Thanks
Dan Wilson
nodans.com
twitter.com/DanWilson
www.linkedin.com/in/profile
ofdanwilson

A Note for MySQL users
[mysqld]
innodb_file_per_table
1. Do a mysqldump of all databases, procedures, triggers etc
except the mysql and performance_schema databases
2. Drop all databases except the above 2 databases
3. Stop mysql
4. Delete ibdata1 and ib_log files
5. Start mysql
6. Restore from dump

Content Delivery Network
PROS
● Caches HTTP Response
● Ajax Friendly
● Static Content
● TTL/Manual Purge
● Blazing Fast
● Can be geographically
distributed
● No physical infrastructure to
manage
● Pay for what you use
CONS
● Pay for what you use
● SSL is more complicated
● Testing is more complicated
● Reliant on external service
● Not a good fit for intranet
traffic

Content Delivery Options
www.akamai.com
aws.amazon.com/cloudfront

Monitoring Options
ColdFusion Server
Monitor
CFStat
New Relic – SaaS
Fusion Reactor Monitor
Nagios

Reverse Proxy Cache (Front Cache)

Reverse Proxy Cache
PROS
● Caches HTTP Response
● Ajax Friendly
● Static Content
● TTL/Manual Purge
● Blazing Fast
● Many Open Source
Products
● Low operating expense
● Can be used for intranets
CONS
● Personalization must be
client side (no session
scope)
● Content is treated as static
● Testing is more complicated
● Must Manage Physical
Infrastructure
● Often Geographically
Localized

Key Value Store
PROS
● Blazing Fast
● Can cache any in-memory
item
● Some caches are
sophisticated, some
aren't
● Can be distributed
● Simple interfaces
● Integrated in CF
CONS
● Many Cached Items
represent an HTTP
request
● What is real-time to your
application?
● Key management can
be hard
● WYCIWYG (what you
cache is what you get)

Helpful Links
In-Memory Cache
Reverse Proxy
http://www.ehcache.org
Cache
http://terracotta.org/coldfusio
http://varnish-cache.org
n
Tutorials on Caching
http://Scalability www.squid-cache.org
http://memcached.org
Blogs
http://trafficserver.apache.org Varnish: http://bit.ly/c1puD6
http://cfwhisperer.com
Squid Video: http://bit.ly/9iZu1Z
http://highscalability.com
Aaron West: http://bit.ly/a4sYcr
Rob Brooks-Bilson: http://bit.ly/txser
Terracotta Webinar: http://www.terracotta.org/webcasts
This presentation: http://tinyurl.com/cacheme

Top5 scalabilityissues

More Related Content

What's hot (20)

Viewers also liked (20)

Similar to Top5 scalabilityissues (20)

More from ColdFusionConference (20)

Recently uploaded (20)

Top5 scalabilityissues