VIDEO: https://youtu.be/atnWLcVhjlg Using cache in highly scalable systems, best practices, main concepts.

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
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