Zend Server:
Scalability & Performance
By Shahahr Evron
Technical Product Manager, Zend Technologies

Welcome!
I am:
▶ A PHP programmer since 2002
▶ At Zend since 2005
▶ Technical Product Manager for Zend Server
Yes, I have a difficult name (at least for English speakers)
▶ Shachar (German, Dutch)
▶ Shajar (Spanish)
▶ Шахар (Russian)
▶ ‫( ﺷﺨﺮ‬Arabic)
▶ ‫( שחר‬Hebrew)
2

Agenda
▶ What is Zend Server?
▶ Performance and Scalability
▶ Zend Server's approach to performance
▶ Out of the box performance: Optimizer+
▶ Setting it up to run faster
▶ Caching, Caching, Caching
▶ Task off-loading and off-line processing
3

What is Zend Server?
...and why should I care?
4

...Well, Just ask your friend at marketing!
“Zend Server is a complete, enterprise-
ready Web Application Server for
running and managing
PHP applications that require a high
level of reliability, performance and
security.”
5

Let's try to make sense out of that..
Zend Server Is:
▶ A complete, well tested PHP runtime environment
▶ Supported and updated by Zend
▶ Comes with a set of extra features that:
●
Improve the performance and reliability of PHP applications
●
Make it easier to manage a consistent PHP environment
Comes in two flavors:
▶ Zend Server
▶ Zend Server Community Edition
6

Performance & Scalability
Some terminology
7

What performance are we talking about?
Improving an application's performance can mean:
▶ Making it run faster
●
More requests per second on the server side
●
Less load time on the user side
▶ Making it run more efficiently
●
Use less memory / CPU / disk IO / network bandwidth
●
Distribute load evenly over time / hardware
These are not always the same, and setting goals is
important!
8

What about Scalability?
Scalability can mean different things:
▶ Ability to gracefully handle more users
▶ Ability to gracefully handle more data
▶ Ability to gracefully handle more code
Scalability can be improved by performance
optimizations...
▶ But they are not the same, and sometimes even conflict!
9

Zend Server's approach to Performance
10

Comprehensive Performance
A Web App's performance depends on many factors...
▶ Network
▶ Web server load
▶ PHP processing time
▶ Database load
▶ Application logic
▶ ...?
...that is why improving your applications performance
will require applying a range of measures
▶ Zend Server provides a set of different tools to help you do that!
11

It's just a series of tubes, right?
12

Out of the box performance
Performance 101
13

Opcode Caching and Optimization
Zend Server includes Optimizer+:
▶ PHP Opcode is read once from disk and compiled
▶ The compiled opcode goes through a set of optimizations
▶ The optimized opcode is stored in shared memory
●
No need to read from disk again unless the code changes
●
No need to compile the code on each request / file inclusion
● Optimized code potentially executes faster
▶ Works out of the box, no setup needed!
● Can be made even better with some tuning :)
14

How Optimizer+ Works?
15

How Optimizer+ Works?
16

How Optimizer+ Works?
17

Optimizer+: A quick Benchmark
Bare PHP Optimizer+
50
45.55
45 41.73
40
35
30
25
20
15 13.96 12.69
10
5.3
5 2.24
0
Magento Drupal SugarCRM CE
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Setting it up to run faster
Tuning tips
19

Tuning Zend Server for Performance
Zend Server comes with a default “good for all” setup
▶ You should go over the performance guide when moving to
production!
Some things you should definitely do:
▶ Turn off extensions you don't need
▶ Tune PHP configuration
▶ Tune Zend Monitoring Rules
20

Turn off extensions you don't need
Why load extensions you don't use?
▶ Per-process memory can be reduced
▶ Less work at MINIT and possibly at RINIT / RSHUTDOWN
▶ Generally a good security practice
A quick test on per-process Apache memory usage shows:
▶ With 55 extensions: 9.3mb
▶ With 31 extensions: 7.2mb
●
Almost 30% more concurrent requests on an average machine!
Of course, you must know what can be turned off...
21

Tune PHP configuration
Many PHP directives can be optimized for performance
▶ Those have relatively small effect
▶ ...but they are easy to fix, and you should know them!
Here are some examples:
▶ include_path, realpath_cache_size, realpath_cache_ttl
▶ output_buffering
▶ register_long_arrays, register_argc_argv
▶ magic_quotes_gpc
▶ error_reporting
▶ memory_limit, max_execution_time
▶ session.auto_start
22

Caching, Caching, Caching
23

Caching?
“In computer science, a cache is a collection of
data duplicating original values stored elsewhere
or computed earlier, where the original data is
expensive to fetch or to compute, compared to the
cost of reading the cache.”
-- Wikipedia
24

Caching with Zend Server...
Zend Server provides several caching tools
▶ Zend Data Cache
●
Disk storage
●
Shared memory storage
▶ Zend Page Cache
▶ Common Caching Extensions
● memcache
● APC compatibility layer
You can get the best results by combining some or all of
those
▶ You can abstract storage backends using ZF's Zend_Cache
25

Page Caching
Page Caching allows you to cache full HTTP responses
▶ Super fast!
▶ Based on a rule system – no code changes required
▶ Cached / live decision can be based on request or session data
▶ Variants can be created based on request or session data
▶ Client-side caching is utilized if supported by browser
Setting it up requires some careful planning
...but the performance gains are usually worth the effort
26

Page Caching
27

Page Cache: A Quick Drupal Benchmark
Caching node pages for guest users
▶ Can be done with no effort using a SESSION based rule
▶ Much better results can be achieved using a COOKIE based rule
●
...no need to run code up to session_start
700
589.26
600
500
400
300
201.17
200
100
21.94
0
No Cache Session Rule Other Rule
28

Data Caching
Zend Server's Data Caching API allows you to:
▶ Programatically place data items into cache
●
And also get them and delete them ;)
▶ Use shared memory or disk storage as needed
▶ Organize cached items into namespaces
▶ Clear cached content from Zend Server's UI
Data Caching more of a “precision guided” caching tool
▶ Requires code changed (but is easy to use)
▶ Not as effective performance wise as Page Cache
▶ Very flexible
29

Data Caching
function getRecentPosts($count = 5) {
// Try to fetch from the cache first
$recentPosts = zend_shm_cache_fetch('recentposts-' . $count);
if ($recentPosts === false) {
// Get the PDO adapter for the DB
$dbAdapter = myBlogDb::getPdoAdapter();
// Build the query
$query = "SELECT title, author, pubdate FROM posts ORDER BY pubdate DESC LIMIT ?";
$dbStatement = $dbAdapter->prepare($query);
// Execute the query
$recentPosts = array();
if ($dbStatement->execute(array($count))) {
while($post = $dbStatement->fetch(PDO::FETCH_ASSOC)) {
$recentPosts[] = $post;
}
// Store the results in cache
zend_shm_cache_store('recentposts-' . $count, $recentPosts, 24 * 3600);
}
}
return $recentPosts;
} Read more: http://devzone.zend.com/article/4457
Or just Google “Zend Server Caching Guide”
30

Off-line processing & Task off-loading
Why do now the stuff you can do later?
31

Job Queue
Off-line processing?
▶ Web applications tend to “live” in HTTP request/response cycles
▶ What do you do when you need to take something off-line?
▶ What do you do when you need periodical execution?
It's also a matter of user experience:
▶ Sometimes, it's just silly to let the user wait
Zend Server Job Queue allows you to take it off-line!
▶ Run things asynchronously, later, on a different server
▶ Run things periodically
32

So is it some glorified Cron?
No!
▶ You can run things now, but without waiting for them to finish
▶ You can run things once, but not right now
▶ You can run things periodically (like cron)
●
But have full control over them – start, stop, suspend, resume from
PHP API
▶ Job Queue gives you full visibility into what's going on
● Get alerts on failed jobs, analyze errors and re-queue
● Keep track of past, current and pending jobs
● Integrates with Zend Monitor
▶ You don't need to hack it all to work for you
33

Job Queue – a Common Execution Flow
34

Job Queue – a Common Execution Flow
35

Job Queue
Front-end code:
if (GlobalConfig::get('useJobQueue')) {
// Use job queue to off-load email sending
$params = array(
'recipients' => $recipients,
'message' => $message
);
$queue = new ZendJobQueue();
$queue->createHttpJob('http://localhost/mail/job.php',
$params);
} else {
// No job queue, send emails directly
send_mail($recipients, $message);
}
36

Job Queue
Back-end code:
$params = ZendJobQueue::getCurrentJobParams();
if (isset($params['recipients']) &&
isset($params['message'])) {
send_mail($params['recipients'], $params['message']);
ZendJobQueue::setCurrentJobStatus(ZendJobQueue::OK);
} else {
ZendJobQueue::setCurrentJobStatus(ZendJobQueue::FAILURE,
"Missing recipients list or message");
}
37

Job Queue
Baseline Job Queue
140 128.81 127.82 128.61
120
100
80
60
40
20 9.39
3.38 1.5
0
1 recipient 3 recipients 6 recipients
38

Zend Download Server
Quick & Easy Apache Efficiency
39

What is Zend Download Server
If you use Apache in Prefork mode:
▶ Each process handles one request at a time
▶ Your server's # of processes is limited (usually by RAM)
▶ Once your server's processes are maxed, you have a problem!
Solutions:
▶ Add more hardware (← last resort!)
▶ Switch to a threaded web server + FastCGI PHP
●
lighttpd, optimized threaded Apache, nginx etc.
▶ Off-load static downloads
●
To a separate web server, separate machine, CDN / 3rd party storage
▶ Set up Zend Download Server!
40

How does Zend Download Server help?
Zend Download Server improves Apache's scalability by:
▶ “Hijacking” static downloads to a separate, efficient process
▶ Freeing Apache processes to do the “hard work” (== PHP)
Usage modes:
▶ Can be set up to automatically send specific file types
▶ Can be used through API (zend_send_file, zend_send_buffer)
Benefits:
▶ Easy to set up and use, no code changes
▶ Easy to integrate with your PHP app's logic
● e.g. authenticated downloads
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Epilogue
42

Conclusions
43

Conclusions
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Conclusions
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Conclusions
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Conclusions
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Conclusions
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Conclusions
49

Thanks!
Email me: shahar.e@zend.com
Learn more at http://www.zend.com/server
Copyright © 2009 Zend Technologies Ltd.
This work is licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. To view a copy of
this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 171 Second Street,
Suite 300, San Francisco, California, 94105, USA.
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