Slides for my talk on Caching at #ndcoslo 2016

1. Caching
Go big or go home
Harald Schult Ulriksen
@hsulriksen

3. HTTP Cache
Output
cache
Application
cache

4. RFC 7234 - HTTP/1.1 Caching

5. RFC 7234 - HTTP/1.1 Caching
A stored response can be considered fresh
if the response can be reused without validation

6. RFC 7234 - HTTP/1.1 Caching
Although caching is an entirely OPTIONAL feature of HTTP, it can be
assumed that reusing a cached response is desirable and that such
reuse is the default behavior when no requirement or local
configuration prevents it. Therefore, HTTP cache requirements are
focused on preventing a cache from either storing a non-reusable
response or reusing a stored response inappropriately, rather than
mandating that caches always store and reuse particular responses.

7. RFC 7234 - HTTP/1.1 Caching
Freshness
• s-max-age
• max age
• Expires
• heuristics

8. RFC 7234 - HTTP/1.1 Caching
Freshness
• s-max-age
• max age
• Expires
• heuristics
Last modified Last requested Now
Tid

9. RFC 7234 - HTTP/1.1 Caching
Freshness
• s-max-age
• max age
• Expires
• heuristics
Validation - RFC 7232
• Etag
• Last-Modified
• If-none-match
• If-modified-since

10. RFC 7234 - HTTP/1.1 Caching
Links
• RFC 7234 - https://tools.ietf.org/html/rfc7234
• RFC 7232 - https://tools.ietf.org/html/rfc7234
• Mark Nottingham - https://www.mnot.net/cache_docs
• Darrel Miller - http://bizcoder.com/caching-is-hard-draw-me-a-
picture
• Jesse Wilson – https://publicobject.com/2015/03/26/how-do-http-
caching-heuristics-work

11. Application cache
• ASP.NET Core (or Microsoft.extensions.caching)
• Local cache
• Redis
• Redis with msgpack
• Distributed layered cache
• With synchronization

12. Microsoft.Extensions.Caching

13. Microsoft.Extensions.Caching
IMemoryCache
• Powered by dictionary
• Supports callback on
eviction.
• Has priority on items in
cache
• Compacts on GC Gen2

14. Microsoft.Extensions.Caching
IMemoryCache
• Powered by dictionary
• Supports callback on
eviction.
• Has priority on items in
cache
• Compacts on GC Gen2
IDistributedCache
• MemoryCache
• Redis
• SQL Server
• You do the serialization

15. Local cache

16. Demo

17. Remote cache

18. Remote cache

19. Remote cache

20. Redis
• http://redis.io
• Key value store + data structures
• By Salvatore Sanfilippo / @antirez
• Ansi C
• Single threaded
• Lua in server
• Microsoft research port to windows – nuget redis-64
• On Azure, AWS og Google cloud.

21. Demo

22. In production

23. Layered distributed cache
Application Local cache Remote cache Slow thing

24. Demo

25. Pub-sub
1
2
3
4
1.Store data
2.Send publish notification
3.Publish notification
4.Get data

26. Demo

27. In production

28. In production