2. What is Redis
An open source, BSD licensed,
advanced key-value store
Sponsored by

3. Who's using Redis?

4. Supported Platforms
 Linux
 Mac OS X
 FreeBSD
 Solaris
 Windows
 no official support

5. Supported Languages
 ActionScript
 C
 C++
 C#
 Clojure
 Common Lisp
 Dart
 Erlang
 Go
 Haskell
 Haxe
 Java
 Io
 server-side JavaScript (Node.js)
 Lua
 Objective-C
 Perl
 PHP
 Pure Data
 Python
 Ruby
 Scala
 Smalltalk
 Tcl

6. Data types
 Strings
 with a maximum of 512MB
 Lists
 Sets
 Sorted sets
 Set with score
 Hashes
 Perfect to represent object

7. Commands
 SET
 GET
 INCR
 DECR
 LPUSH
 LRANGE
 LLEN
 EXPIRE
 TTL
 SADD
 SMEMBERS
 SCARD
 SREM
 ZADD
 ZRANGE
 ZREVRANGE
 ZCARD
 ZREM
 HSET
 HGET
 HGETALL

8. Publish–subscribe
 Redis supports publish-subscribe mode.
 You can subscribe some topics, and
when someone publish topic matches
your interest, redis send it to you.

9. Lua scripting
 Scripting makes Redis much faster for
complex operations
 read-compute-write workflow

10. Pipelining
 NOT Redis transactions
 Does not provide atomicity
 Nothing more complicated than the fact
that Redis server is able to queue up
responses in memory
 Too many commands in a single pipeline
may cause memory issues and potentially
socket timeout.
Benchmark
without pipelining 1.185238 seconds
with pipelining 0.250783 seconds

11. Transactions
 All the commands in a transaction are
serialized and executed sequentially.
 Either all of the commands or none are
processed.
 Redis does not support roll backs
 A command fails to be queued
 A command fails after EXEC is called(not
supported)

12. More use cases
 Leader election
 Counting semaphores
 Queue
 Pizza topping problem

13. Persistence
 Virtual Memory
 RDB (Snapshots)
 Take snapshot in an interval
 Fast
 May loss several minutes data if kill -9
 Append Only File (AOF)
 Log-based link binlog, redo whole steps since
startup
 Auto bgrewriteaof (background rewrite AOF)
 Still fast enough
 May loss 1 second data if kill -9

14. Replication
 Official Master-slave replication
 Write in Master, Read in Slaves
Replication
• Official Master-slave replication
– Write in Master, Read in Slaves

15. Partitioning
 Redis Cluster is currently not production
ready.
 Redis Cluster is a mix between query
routing and client side partitioning.

16. High Availability
Redis Sentinel is a system designed to
help managing Redis instances. It
performs the following three tasks:
 Monitoring
 Notification
 Automatic failover
 Not good for production environments

17. High Availability(alternative)
 Virtual IP
 keepalived or heartbeat
 DRBD

18. High Availability(alternative)
 redis_failover project

19. Twemproxy
 Maintain persistent server connections
 Keep connection count on cache servers low
 Pipeline requests and responses
 Use multiple server pools simultaneously
 Proxy the complete memcached ASCII
protocol
 Easily configure server pools using a YAML file
 Use multiple hashing modes, including
consistent hashing
 Increase observability using stats exposed on
a monitoring port

20. Performance Benchmark

21. Cost of Redis Persistence

22. Redis web admin console
 Redis Commander
 Redmon
 Redsmin

23. Redis Commander
 Asfd

24. Compare with Memcached

25. Compare with Memcached
Memcached Redis
(Multi)Get V V
(Multi)Set V V
Incr/Decr V V
Deletion V V
Expiration V V
Range Queries V
Data Types V
Persistence V
Replication V
Prepend/Append V
勝
勝
勝
勝
勝

26. Reference
 Redis Commands
 Is memcached a dinosaur in
comparison to Redis?
 Redis Failover at Spreecast Based on
Apache ZooKeeper
 twemproxy

27. Questions?