Web Development, Web application caching techniques.

1. Web Application
Caching
DB ORM Caching
Gamal Shaaban
International Centers
Orange Labs P&S Cairo
Mobile Applications & Software Development

2. Agenda
• Why Caching
– The Theory of Caching
• ORM Caching
– 1st Level of Caching
– 2nd Level of Caching
– Query Caching

3. Why Caching?

4. Why Caching
How much faster will caching make an
application?

5. Why Caching
It depends on a multitude of factors being:
• how many times a cached piece of data can and is
reused by the application.
• the proportion of the response time that is alleviated
by caching.
• In applications that are I/O bound, which is most
business applications, most of the response time is
getting data from a database. Therefore the speed up
mostly depends on how much reuse a piece of data
gets.

6. Why Caching
Amdahl's Law & How to calculate entire system
speed up.
• Amdahl's law, after Gene Amdahl, is used to
find the system speed up from a speed up in
part of the system.
1/ ((1 - Proportion Sped Up) + Proportion Sped Up / Speed up)

7. Why Caching
Speed up from a Web Page Cache
Un-cached page time: 2 seconds
Cache retrieval time: 2ms
Proportion: 100%
The expected server side system speedup is:
1 / ((1 - 1) + 1 / 1000)
= 1 / (0 + .001)
= 1000 times system speedup
The to the browser “system” speed up is much less

8. Why Caching
Speed up from a Database Level Cache
Un-cached page time: 2 seconds
Database time: 1.5 seconds
Cache retrieval time: 2ms
Proportion: 75% (1.5/2)
The expected server side system speedup is:
1 / ((1 - .75) + .75 / (1500/2)))
= 1 / (.25 + .75/750)
= 3.98 times system speedup
The to the browser “system” speed up is much less

9. Why Caching
Non-uniform distribution

10. ORM Caching

11. ORM Caching
1st Level Cache
Session Caching:
– Enabled by default.
– Used transparently during the session.
– All objects that was saved or retrieved
• save
• get
• list

12. ORM Caching
1st Level Cache
Session Caching:
– flush() - will sync cache to DB.
– clear() - will evict all objects.

13. ORM Caching
2nd Level Caching

14. ORM Caching
2nd Level Caching

15. ORM Caching
Cache Providers
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EhCache.
OSCache.
JBoss Cache (AKA Infinispan).
WarmCache.
Hazelcast.
Oracle Coherence.
Gigaspaces.
GemFire

16. ORM Caching
Caching Strategies
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Read-only
Read-write
Transactional
Nonstrict-read-write

17. ORM Caching
Caching Types
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Memory Caching
Disk stores
Clustered (distributed Caching)
Server Caching (RESTful cache server).

18. Questions ?

19. Thank You