Charla sobre Redis impartida en el grupo de Ruby Zaragoza explicando qué es Redis, para qué se usa en sitios como Twitter o Pinterest y cómo se está usando en teowaki
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Por que deberias haberle pedido redis a los reyes magos
1. Por qué deberías haberle
pedido Redis a los Reyes
Magos
javier ramirez
@supercoco9
3. In the beginner's
mind there are many
possibilities, in the
expert's mind there
are few.
Shunryu Suzuki
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
5. Intel(R) Xeon(R) CPU E5520 @ 2.27GHz (with pipelining)
$ ./redis-benchmark -r 1000000 -n 2000000 -t get,set,lpush,lpop -P 16 -q
SET: 552,028 requests per second
GET: 707,463 requests per second
LPUSH: 767,459 requests per second
LPOP: 770,119 requests per second
Intel(R) Xeon(R) CPU E5520 @ 2.27GHz (without pipelining)
$ ./redis-benchmark -r 1000000 -n 2000000 -t get,set,lpush,lpop -q
SET: 122,556 requests per second
GET: 123,601 requests per second
LPUSH: 136,752 requests per second
LPOP: 132,424 requests per second
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
6. myth: Redis is just like
memcached
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
7. myth: Redis is for queues
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
8. open source, BSD licensed, advanced
key-value store. It is often referred to as a
data structure server since keys can contain
strings, hashes, lists, sets and sorted sets.
http://redis.io
started in 2009 by Salvatore Sanfilippo @antirez
103 contributors at
https://github.com/antirez/redis
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
10. The Redis Manifesto
1.A DSL for Abstract Data Types
2.Memory storage is #1
3.Fundamental data structures for a
fundamental API
4.Two levels of API
5.Code is like a poem; it's not just something
we write to reach some practical result
6.We're against complexity
7.We optimize for joy
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
15. basics: sets
cool example about sunionstore
http://robots.thoughtbot.com/post/46335890055/redis-set-intersection-using-sets-to-filter-data
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
16. Redis as a PUBSUB system
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
18. Persistance: RDB
Compact binary format
Saves snapshots every few minutes
Good for backups and synchronizing
If Redis crashes, a few minutes worth of
data will be lost
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
19. Durability: AOF
Log text format
Configurable durability
Large file, can slow down startup
If Redis crashes, typically one second of
data could be lost
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
20. replication & scaling out
one master, several
read-only slaves
sharding
Twemproxy & redis cluster
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
21. atomicity
single threaded, so no
concurrency problems
transactions and lua
scripts to run multiple
operations atomically
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
22. Scripting with lua
You can use Lua for scripting Redis when you need to
atomically execute a sequence of commands in which
the output of a command is used as input for another
It reduces the need to use complex lock mechanisms
and simplifies dependencies between clients
You can even extend the functionality of Redis by using
Lua scripts
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
23. what's being used for
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
24. twitter
Every time line (800 tweets
per user) is on redis
5000 writes per second avg
300K reads per second
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
25. twitter
write API (from browser or client app)
follo
e per
on
user id
tweet id
wer
fanout (flockDB)
metadata
rpushx to Redis
user info from
gizmoduck
(memcached)
javier ramirez
@supercoco9
tweet info from
tweetypie
(memcached + mysql)
https://teowaki.com
your twitter
timeline
madrid rb 2013
26. pinterest object graph
from mysql+memcached
to redis
30% save on IOps
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
27. per user
Redis SortedSet, with timestamp as the score, is used to
store the users followed explicitly.
Redis SortedSet, with timestamp as the score, is used to
store the users followed implicitly
Redis SortedSet, with timestamp as the score, is used to
store the user’s explicit followers
Redis SortedSet, with timestamp as the score, is used to
store the user’s implicit followers
Redis Set is used to store boards followed explicitly
Redis Set is used to store boards unfollowed explicitly
per board
Redis Hash is used to store a board’s explicit followers
Redis Set is used to store a board’s explicit unfollowers
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
28. viacom
Object dependency graph. Cache on steroids
Redis as a queue for background jobs
Activity tracking and view counts buffering before saving
to mysql
Lua script working on a slave to recalculate ranking and
popularity of contents, then send the data to master.
The new process takes 1/60th less than the old one in
mysql
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
29. openredis
redis as a service on AWS
serving over 1000
customers with a single
machine
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
30. when things go wrong
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
31. the instagram case
moving from redis to
cassandra: 75% savings on
servers
lesson learnt:
know when redis is not appropriate
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
32. the twilio case
credit card hell
lesson learnt:
know what you are doing.
Don't change config on the fly
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
33. how teowaki is using redis
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
34. Abusing sidekiq/resque
keep track of every activity in the system, even if you
don't need them all right now:
- every page view
- every API request
- every time a record is created/updated/deleted
benefits:
- highly decoupled system
- easier to divide into services
- you can add behaviour without changing your app
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
35. intermediate cache
* As a very fast lightweight storage for analytics data before
sending them to our google bigquery based solution
* As a cache for AR attributes frequently “plucked” or included
and plucked (names, nicknames, guids, delegated or
included model names...)
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
36. Some of our uses of Lua
Expiring attributes inside a Redis hash
Inserting notifications into a list only if there are not
pending notifications from the same user for the
same scope
Paginating a list by an attribute
Manipulating JSON directly at the Redis layer
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
37. counters
Atomic counters can be safely invoked concurrently
from anywhere, so you can implement “like”
features, global sequences or usage monitoring
systems in highly concurrent applications for free.
You can share your counters with any other internal
application and still be sure they won't collide.
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
38. Temporary data
Redis allows us to self expire keys after a time has
passed. You can use this mechanism for a simple
cache
If you operate on a key with expiration time, you
can change its value and still keep the expiration
going. By combining a decrementing counter with
an expiration time, implementing usage quotas is
trivial
Also, you can inspect which keys you have in your
server efficiently using SCAN commands
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
39. bloom filters
bloom filter: space-efficient probabilistic data
structure that is used to test whether an element is
a member of a set. False positive matches are
possible, but false negatives are not.
Redis bit operations make easy to implement bloom
filters
We are using bloom filters for checking uniqueness
of user names and reserved words without going to
postgresql
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
40. nginx + lua + redis
apache + mruby + redis
Multiple levels of cache by using Redis on the webserver/
middleware layer
http://wiki.nginx.org/HttpRedis
https://github.com/jodosha/redis-store
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
41. summarizing
* Redis is more powerful than it seems
* Very fast, easy to use, simple, good documentation
* In-memory data structures, distributed, shared and persisted
* Good as data store, intermediate data store, cache or queue
* Lots of use cases, both in huge and smaller systems
You should probably use it a lot more
javier ramirez
@supercoco9
https://teowaki.com
madrid rb 2013
42. Find related links at
https://teowaki.com/teams/javier-community/link-categories/redis
¡Gracias!
Javier Ramírez
@supercoco9
madrid rb 2013