This presentation is on the basics of web application cache. With the opcode cache, memcache, CDNs....

1.
Web Application Caching

2. What is
Caching?
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Web application caching is the process of storing dynamically generated data
for reuse and leaving data closer to the end user.
Caching used to store static & dynamic data.
For static (js, images, css) there are different kind of caching mechanism used,
CDN : akamai, maxcdn,
For application File, object cache opcode cache get used : APC, eaccelarator,
wincache, xcache
For dynamic data caching Memcache, Redis,
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3. Why to use
Caching?
• To improve web application performance
• To minimize the requests to the server
• Even small performance improvements from caching can drastically
improve the user experience.
• Reduced server workload can translate to reduced hardware and support
costs.
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4. Type of caches
• Opcode Cache : APC, eAccelerator, Wincache, Xcache
• Query Result cache : Memcache, Redis
• CDNs : Content Delivery Networks
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5. APC
• APC : Alternative PHP Cache
• That heavily optimizes and tunes the output of the PHP bytecode compiler and stores
the final, compiled result in shared memory.
• This bytecode optimization leads to faster runtime execution since source files do not
need to be recompiled
• re-use the compiled code rather than having to retrieve the opcodes from a disk cache,
• 3x increase in page generation speed
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6. APC
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7. Memcache
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Key Value pair
Slabs, pages, chunks
A slab class is a collection of pages divided into same sized chunk.
Each slab class has one or more pages, The page is of a predefined size (default
1MB). So, depending on the chunk size each page has a certain number of chunks
and some space left over wasted
• LRU is rescue : When memory gets full, so no pages can be created, the LRU (Least
Recently Used) algorithm kicks in.
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8. Memcache
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9. CDNs
• A content delivery network or content distribution network (CDN)
• large distributed system of servers deployed in multiple data centers
across the Internet
• The goal of a CDN is to serve content to end-users with high availability
and high performance.
• CDN serves : static files like js, css, images, text files
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10. CDNs
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11. Thank You
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