PHP Everyone loves PHP

Agenda PHP Basics Why PHP is so popular in Web 2.0 world Comparison of various platforms (php, ruby, java) Scaling out Database tier Scaling out Web tier Caching (APC/Memcached)

PHP Basics

Why PHP is so popular in Web 2.0 world

Comparison of various platforms (php, ruby, java)

Scaling out Database tier

Scaling out Web tier

Caching (APC/Memcached)

PHP Basics

What is PHP? Server side Scripting language Virtual Machine : Zend Engine Written in C Object Oriented (from PHP 5.0) Weak typing

Server side Scripting language

Virtual Machine : Zend Engine

Written in C

Object Oriented (from PHP 5.0)

Weak typing

Cool Stuff – PHP Array

PHP Array an ordered map - A map is a type that associates values to keys

an ordered map - A map is a type that associates values to keys

<?php $arr = array( &quot;foo&quot; => &quot;bar&quot; , 12 => true ); echo $arr [ &quot;foo&quot; ]; // bar echo $arr [ 12 ]; // 1 ?>

<?php $arr = array( &quot;foo&quot; => array(1, 2) , 12 => array( “ user1 ”=>array( “ name” => ‘mark’, “ gender” => ‘male’ ) ) ); ?>

Juggling with variables

Why PHP is so popular in Web 2.0 world 99880… Larry@… Larry 98778… Mark@… Mark phone email name

Execute Query Select * from <table> where email = ‘Mark@…’

What is returned from DB is a PHP Array object $arr = array( “ name&quot; =>”Mark”, “ email&quot; =>”Mark@…”, “ phone&quot; =>”98778…”, )

The same object can be pushed to JAVA-Script layer for Processing var jsvar = array( “ name&quot; =>”Mark”, “ email&quot; =>”Mark@…”, “ phone&quot; =>”98778…”, )

So what we gained … No need to have an intermediate object like java beans to store the DB result PHP array can be sent directly to javascript layer for processing Java script array notation is same as php array notation … No need to write unnecessary code to handle the DB  Front end communication

No need to have an intermediate object like java beans to store the DB result

PHP array can be sent directly to javascript layer for processing

Java script array notation is same as php array notation …

No need to write unnecessary code to handle the DB  Front end communication

Scaling

Terminology: Scaling NOT how fast your code is How fast your code will be tomorrow Can it scale out? Run in parallel?

NOT how fast your code is

How fast your code will be tomorrow

Can it scale out?

Run in parallel?

Scale out or Scale up ?

Cloud Computing Amazon Cloud

Amazon Cloud Components Amazon Elastic Cloud Computing (EC2) Amazon Simple Storage Service (S3) Amazon Simple Queuing service (SQS) Utilities Distributed computing framework (HADOOP) Amazon Payment service

Amazon Elastic Cloud Computing (EC2)

Amazon Simple Storage Service (S3)

Amazon Simple Queuing service (SQS)

Utilities

Distributed computing framework (HADOOP)

Amazon Payment service

Growing Up, “One Box” solution Basic web application (discussion board, etc.) Low traffic Apache/PHP/MySQL on one machine Bottlenecks will start showing up: Most likely database before apache/php Disk I/O (Innodb) or locking wait states (MyISAM)

Basic web application (discussion board, etc.)

Low traffic

Apache/PHP/MySQL on one machine

Bottlenecks will start showing up:

Most likely database before apache/php

Disk I/O (Innodb) or locking wait states (MyISAM)

InnoDB vs. MyISAM

90% Read 60% Read 99880… Larry@… Larry 98778… Mark@… Mark phone email name I like it … Photo #4 Larry@… This is great Photo #1 Mark@… comment resource email

Growing Up, “Two Box” solution Higher traffic application Apache/PHP on Box A, MySQL on Box B Bottlenecks will be Disk I/O on MySQL Box Locking on MyISAM tables Network I/O

Higher traffic application

Apache/PHP on Box A, MySQL on Box B

Bottlenecks will be

Disk I/O on MySQL Box

Locking on MyISAM tables

Network I/O

Growing Up, “Many Boxes with Replication” solution Yet even higher traffic Writes are separated from reads (master gets IN/UP/DEL, slaves get SELECTs) SELECTs, IN/UP/DEL can be specified within the application, Or Load-balancing can be used

Yet even higher traffic

Writes are separated from reads (master gets IN/UP/DEL, slaves get SELECTs)

SELECTs, IN/UP/DEL can be specified within the application,

Or

Load-balancing can be used

Bottlenecks … As you have multiple slaves Your code will decide “Execute Select command in Slave #4” But how will you decide it ?

As you have multiple slaves

Your code will decide “Execute Select command in Slave #4”

But how will you decide it ?

Using Hardware Load Balancer

How its usually done? Standard MySQL Master/Slave replication All writes (Insert/Delete/Update) from application go to master All reads (Selects) from application go to a load balancer which will spread out load across all slaves.

Standard MySQL Master/Slave replication

All writes (Insert/Delete/Update) from application go to master

All reads (Selects) from application go to a load balancer which will spread out load across all slaves.

What is good about load balancing ? You can add/remove slaves without affecting the application. Additional monitoring point and automatic failure detection You can treat all your slave pool as one resource.

You can add/remove slaves without affecting the application.

Additional monitoring point and automatic failure detection

You can treat all your slave pool as one resource.

Only one Master Database … the Next Bottleneck …

Use NDB Cluster

Scaling out Web tier

Design Change Store your Session variable in Database Always access Session from DB Remove the Session entry from DB on Logout Update the session entry periodically to handle session hijacking attack …

Store your Session variable in Database

Always access Session from DB

Remove the Session entry from DB on Logout

Update the session entry periodically to handle session hijacking attack …

#1 #2 #3 #4 Load Balancer DB Layer

Caching (APC/Memcached)

Where should we store the value Local database is faster than shared database Local Disk faster than database RAM is faster than disk

Local database is faster than shared database

Local Disk faster than database

RAM is faster than disk

What we will store Anything you don’t want to fetch or compute every time your code runs Anything that’s not going to change very often

Anything you don’t want to fetch or compute every time your code runs

Anything that’s not going to change very often

Everybody is doing it WP_Cache (Wordpress) Memcache Live journal Slashdot wikipedia

WP_Cache (Wordpress)

Memcache

Live journal

Slashdot

wikipedia

Even PHP Itself Is Getting Cached PHP opcode caches compile your scripts and run these pre-parsed versions instead. Zend Optimizer APC (Alternative PHP Cache) Xcache eAccelerator ionCube

PHP opcode caches compile your scripts and run these pre-parsed versions instead.

Zend Optimizer

APC (Alternative PHP Cache)

Xcache

eAccelerator

ionCube

Of course OS caches files Modern operating systems use all your free RAM as a disk cache. If you read the same file over & over, it's probably being read out of RAM the second time on. So, it's usually ok to read a small file over & over.

Modern operating systems use all your free RAM as a disk cache.

If you read the same file over & over, it's probably being read out of RAM the second time on. So, it's usually ok to read a small file over & over.

Memcached memcached is a high-performance, distributed memory object caching system

Thank You