CHAPTER 1: A REFRESHER ON WEB BROWSERS 3

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1 INTRODUCTION xxiii PART I: FRONT END CHAPTER 1: A REFRESHER ON WEB BROWSERS 3 A Brief History of Web Browsers 3 Netscape Loses Its Dominance 4 The Growth of Firefox 4 The Present 5 Inside HTTP 5 The HyperText Transfer Protocol 5 HTTP Versions 8 Support for Virtual Hosting 9 Caching 9 How Browsers Download and Render Content 10 Rendering 11 Persistent Connections and Keep-Alive 12 Parallel Downloading 14 Summary 21 CHAPTER 2: UTILIZING CLIENT-SIDE CACHING 23 Understanding the Types of Caching 23 Caching by Browsers 23 Intermediate Caches 24 Reverse Proxies 25 Controlling Caching 25 Conditional GETs 25 Utilizing Cache-Control and Expires Headers 28 Choosing Expiration Policies 30 Coping with Stale Content 30 How Not to Cache 31 Dealing with Intermediate Caches 31 Cache-Control Revisited 31 Caching HTTP Responses 32 The Shift in Browser Behavior 32 Using Alternative 3xx Codes 34 COPYRIGHTED MATERIAL

2 DNS Caching and Prefetching 34 The DNS Resolution Process 35 DNS Caching by the Browser 35 How DNS Lookups Affect Performance 36 DNS Prefetching 36 Controlling Prefetching 37 Summary 37 CHAPTER 3: CONTENT COMPRESSION 39 Who Uses Compression 39 Understanding How Compression Works 41 Compression Methods 42 Other Compression Methods 47 Transfer Encoding 48 Compression in PHP 49 Compressing PHP-Generated Pages 49 Compressing Other Resources 51 Summary 51 CHAPTER 4: KEEPING THE SIZE DOWN WITH MINIFICATION 53 JavaScript Minification 54 YUI Compressor 55 Google Closure 56 Comparison of JavaScript Minifi ers 58 CSS Minification 59 Use Shorthand 59 Grouping Selectors 60 CSS Minifiers 60 Improving Compression 62 HTML Minification 63 HTML Minifi cation Techniques 64 HTML Minifi cation Tools 66 Summary 69 CHAPTER 5: OPTIMIZING WEB GRAPHICS AND CSS 71 Understanding Image Formats 71 JPEG 72 GIF 72 PNG 73 SVG 73 xiv

3 Optimizing Images 74 Image Editing Software 74 Choosing the Right Format 74 Interlacing and Progressive Rendering 75 PNG Optimization 77 GIF Optimization 80 JPEG Compression 80 Image Optimization Software 84 Data URIs 85 Favicons 85 Using Lazy Loading 87 Avoiding Empty src attributes 88 Using Image Maps 89 CSS Sprites 91 Sprite Strategies 94 Repeating Images 94 CSS Performance 99 CSS in the Document Head 100 Inline versus External 100 Link 100 Redundant Selectors 100 CSS Expressions 101 Selector Performance 102 Using Shorthand Properties 102 Inheritance and Default Values 104 Doing More with CSS 104 Looking Forward 109 MNG 109 APNG 109 JPEG Summary 110 CHAPTER 6: JAVASCRIPT, THE DOCUMENT OBJECT MODEL, AND AJAX 111 JavaScript, JScript, and ECMAScript 112 A Brief History of JavaScript 112 JavaScript Engines 112 The Document Object Model 115 Manipulating the DOM 117 Refl owing and Repainting 117 Browser Queuing 119 xv

4 Event Delegation 119 Unobtrusive JavaScript 120 Memory Management 121 Getting the Most from JavaScript 122 Language Constructs 122 Loading JavaScript 127 Nonblocking of JavaScript Downloads 128 Merging, Splitting, and Inlining 130 Web Workers 134 Ajax 136 XMLHttpRequest 136 Using Ajax for Nonblocking of JavaScript 137 Server Responsiveness 137 Using Preemptive Loading 138 Ajax Frameworks 138 Summary 138 PART II: BACK END CHAPTER 7: WORKING WITH WEB SERVERS 141 Apache 141 Working with Modules 142 Deciding on Concurrency 145 Improving Logging 146 Miscellaneous Performance Considerations 148 Examining Caching Options 150 Using Content Compression 155 Looking Beyond Apache 158 Nginx 158 Nginx, Apache, and PHP 164 The Best of the Rest 168 Multiserver Setups with Nginx and Apache 169 Nginx as a Reverse Proxy to Apache 170 Proxy Options 171 Nginx and Apache Side by Side 172 Load Balancers 173 Hardware versus Software 173 Load Balancer Features 174 Using Multiple Back-End Servers 176 HAProxy 181 Summary 191 xvi

5 CHAPTER 8: TUNING MYSQL 193 Looking Inside MySQL 194 Understanding the Storage Engines 195 MyISAM 195 InnoDB 196 MEMORY 197 ARCHIVE 198 Tuning MySQL 198 Table Cache 198 Thread Caching 202 Per-Session Buffers 204 Tuning MyISAM 205 Key Cache 205 Miscellaneous Tuning Options 210 Tuning InnoDB 211 Monitoring InnoDB 211 Working with Buffers and Caches 212 Working with File Formats and Structures 217 Memory Allocation 218 Threading 219 Disk I/O 219 Mutexes 222 Compression 223 Working with the Query Cache 225 Understanding How the Query Cache Works 225 Confi guring the Query Cache 227 Inspecting the Cache 228 The Downsides of Query Caching 232 Optimizing SQL 234 EXPLAIN Explained 234 The Slow Query Log 237 Indexing 239 Query Execution and Optimization 247 Query Cost 248 Tips for SQL Efficiency 249 Summary 254 CHAPTER 9: MYSQL IN THE NETWORK 255 Using Replication 256 The Basics 256 xvii

6 Advanced Topologies 264 Replication Performance 270 Miscellaneous Features of Replication 273 Partitioning 273 Creating Partitions 274 Deciding How to Partition 276 Partition Pruning 276 Physical Storage of Partitions 277 Partition Management 278 Pros and Cons of Partitioning 278 Sharding 279 Lookup Tables 280 Fixed Sharding 281 Shard Sizes and Distribution 281 Sharding Keys and Accessibility 281 Cross-Shard Joins 282 Application Modifi cations 283 Complementing MySQL 283 MySQL Proxy 283 MySQL Tools 286 Alternatives to MySQL 294 MySQL Forks and Branches 294 Full-Text Searching 296 Other RDBMSs 307 Summary 308 CHAPTER 10: UTILIZING NOSQL SOLUTIONS 309 NoSQL Flavors 310 Key-Value Stores 310 Multidimension Stores 310 Document Stores 311 memcache 311 Installing and Running 312 membase memcache with Persistent Storage 321 MongoDB 325 Getting to Know MongoDB 325 MongoDB Performance 328 Replication 339 Sharding 343 Other NoSQL Technologies 353 Tokyo Cabinet and Tokyo Tyrant 354 CouchDB 354 xviii

7 Project Voldemort 355 Amazon Dynamo and Google BigTable 355 Riak 356 Cassandra 356 Redis 356 HBase 356 Summary 356 CHAPTER 11: WORKING WITH SECURE SOCKETS LAYER (SSL) 359 SSL Caching 360 Connections, Sessions, and Handshakes 360 Abbreviated Handshakes 360 SSL Termination and Endpoints 364 SSL Termination with Nginx 365 SSL Termination with Apache 366 SSL Termination with stunnel 367 SSL Termination with stud 368 Sending Intermediate Certificates 368 Determining Key Sizes 369 Selecting Cipher Suites 369 Investing in Hardware Acceleration 371 The Future of SSL 371 OCSP Stapling 371 False Start 372 Summary 372 CHAPTER 12: OPTIMIZING PHP 375 Extensions and Compiling 376 Removing Unneeded Extensions 376 Writing Your Own PHP Extensions 378 Compiling 379 Opcode Caching 381 Variations of Opcode Caches 381 Getting to Know APC 382 Memory Management 382 Optimization 382 Time-To-Live (TTL) 382 Locking 383 Sample apc.ini 384 APC Caching Strategies 384 Monitoring the Cache 386 Using APC as a Generic Cache 386 xix

8 Warming the Cache 387 Using APC with FastCGI 387 Compiling PHP 388 phc 388 Phalanger 388 HipHop 388 Sessions 389 Storing Sessions 389 Storing Sessions in memcache/membase 390 Using Shared Memory or tmpfs 390 Session AutoStart 391 Sessions and Caching 391 Efficient PHP Programming 392 Minor Optimizations 392 Major Optimizations 392 Garbage Collection 395 Autoloading Classes 396 Persistent MySQL Connections 396 Profiling with xhprof 398 Installing 398 A Simple Example 399 Don t Use PHP 401 Summary 401 PART III: APPENDIXES APPENDIX A: TCP PERFORMANCE 405 The Three-Way Handshake 405 TCP Performance 408 Nagle s Algorithm 408 TCP_NOPUSH and TCP_CORK 408 APPENDIX B: DESIGNING FOR MOBILE PLATFORMS 409 Understanding Mobile Platforms 409 Responsive Content 410 Getting Browser Display Capabilities with JavaScript 411 Server-Side Detection of Capabilities 411 A Combined Approach 412 CSS3 Media Queries 413 Determining Connection Speed 413 xx

9 JavaScript and CSS Compatibility 414 Caching in Mobile Devices 414 APPENDIX C: COMPRESSION 417 The LZW Family 417 LZ LZ LZW 419 LZ Derivatives 420 Huffman Encoding 421 Compression Implementations 424 INDEX 427 xxi