Caching concepts part 1
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The document discusses various caching concepts, including where cache is used and its limitations, particularly in relation to HTTP headers. It emphasizes the importance of consistent caching strategies and proper header utilization to avoid serving stale data, while also making recommendations for effective caching practices. The mention of Sun Tzu highlights the strategic aspect of caching in optimizing performance without unnecessary conflict.
Caching concepts part 1
- 1. Caching Concepts 1 Tomer Ben David
- 2. 1.Sun Tzu view on cache 2.Where used 3.Limitations 4.HTTP headers 5.Recommendations 6.User 7.CDN
- 3. “The supreme art of war is to subdue the enemy without fighting.” –Sun Tzu
- 4. It’s Everywhere: Used in CPU, HDD, DNS, Browsers, Proxies, Reverse Proxies, Shared Cache
- 5. We should be able to rebuild all cache if does not exist
- 6. Trading space for time, eviction policy
- 7. How not to serve stale data?
- 8. Older http cache headers such as "Pragma: no-cache" can be interpreted differently by different servers.
- 9. First header: "Cache-Control" got in response private,max-age=15 (seconds) - this page is for this user and not relevant after 15 seconds
- 10. Expires header, absolute time to expire cache, overlap Cache- Control: max-age
- 11. Recommendation, choose one header type and be consistent
- 12. "Vary": Accept-Encoding => for different Accept-Encoding I have different caches
- 13. Use css as immutable if you have a different version push it under a different URL (for example with the help of hash), this also allows for versioning
- 14. Example per user cache: Cache-Control: private, must-revalidate Expires: Sat, 23 Jul 2015 13:14:28 GMT Vary: Accept-Encoding (must-revalidate) server asks impolitely the client not to use the cache after expires
- 15. Avoid the http meta cache tags instead of headers <meta http-equiv="cache-control" content="max-age=0" /> <meta http-equiv="cache-control" content="no-cache" /> <meta http- equiv="expires" ...
- 16. Caching Players Browser cache --> proxy cache -- > CDN cache --> reverse proxy cache
- 17. SSL prevents proxies from caching
- 18. Cache is not only for css cache also your REST calls
- 19. You can point a subdomain to CDN and CDN forwards to you cachedcdn.mydomain.com If fails/expires forwards requests
- 20. What/Who would you like to hear about? please do comment, and if liked please like :)