The document discusses Memcache and its implementations. Memcache is a fast, dumb server that sits between application servers and databases to improve performance. There are several Memcache implementations including the original Memcached by Danga, Tugela which adds Berkeley DB support, and Memcachedb which adds replication. Memcached generally performs well under normal conditions with enough memory, while Tugela can outperform Memcached on memory-constrained servers or with many simultaneous threads. Tugela lacks expiration policy management so items may expire without purging. The PHP implementation using UDP and consistent hashing from PECL is recommended.

1. Memcache : because
your database will
thank you
http://netuality.ro

3. Spot the
resemblance

4. Memcache stays quot;betweenquot; app servers
and db - dumb/fast server,
client quot;as smart as neededquot;
image © blogs.sun.com

5. Plan for success = no panic
image © www.jangro.com

6. 3 implementations:
- quot;originalquot; memcached
by Danga
danga.com/memcached/
- tugela memcache
(bdb, Wikipedia)
http://tinyurl.com/26jx5e
- memcachedb (bdb,
replicated, student
project on Google Code,
unstable)
- lots of contributions
(Facebook, LastFM)

7. Memcached vs Tugela
- quot;normalquot; conditions, enough memory
- negligible overhead

8. Memcached vs Tugela
- on a memory-constrained server
- 100/1000 simultaneous threads (stackless Python)
- ... and yet Tugela massively kicks ass

9. Tugela gotchas
- “no expiry policy management” = NO PURGING,
ITEMS DO EXPIRE
- but project not maintained any more. Forks
welcomed by the author (Domas Mituzas).
PHP programmer ?
- use UDP and consistent hashing implementation
from PECL, truly rocks
memcache.hash_strategy = consistent