Web application caching stores dynamically generated data for reuse, improving performance and reducing server requests. Different caching mechanisms include opcode caches (APC, eAccelerator), query result caches (Memcache, Redis), and content delivery networks (CDNs) for static data. Implementing caching can lead to significant performance gains and reduced hardware costs.

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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