Fun with ruby and redis, arrrrcamp edition, javier_ramirez, teowaki

Fun
with
&
arrrrcamp 2013javier ramirez @supercoco9 http://teowaki.com arrrrcamp 2013

javier ramirez
@supercoco9
javier ramirez @supercoco9 http://teowaki.com arrrrcamp 2013

hugs
and
hooks:
arrrr you
sure ?

ignaz
semmelweis

In the beginner's
mind there are many
possibilities, in the
expert's mind there
are few.
Shunryu Suzuki

myth: the bottleneck

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

myth: arrrrRedis is just
like memcached

myth: rrrrRedis is for
queues

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
100 contributors at
https://github.com/antirez/redis

hacker
meets
thinker*
*@janogonzalez and @advi inspired slide

The arrrrRedis 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

basics: setting and getting

basics: lists

basics: counterrrrrs

basics: hashes

basics: sets
cool example about sunionstore
http://robots.thoughtbot.com/post/46335890055/redis-set-intersection-using-sets-to-filter-data

Redis keeps
everrrrrything
in memorrrrry
all the time

Perrrrrsistance: 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

Durrrrrability: AOF
Log text format
Configurable durability
Large file, can slow down startup
If Redis crashes, typically one second of
data could be lost

rrrrreplication
one master, several
read-only slaves
sharding
Twemproxy & redis cluster

atomicity
single threaded, so no
concurrency problems
transactions and lua
scripts to run multiple
operations atomicallyjavier ramirez @supercoco9 http://teowaki.com arrrrcamp 2013

Scrrrrripting 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

what's being used forrrrr

twitterrrrr
Every time line (800 tweets
per user) is on redis
5000 writes per second avg
300K reads per second

twitter
user info from
gizmoduck
(memcached)
user id tweet id metadata
write API (from browser or client app)
rpushx to Redis
tweet info from
tweetypie
(memcached + mysql)
your twitter
timeline
fanout (flockDB)
one per follower

pinterest object grrrrraph
from mysql+memcached
to redis
30% save on IOps

per userrrrr
Redis SortedSet, with timestamp as the score, is used to
store the users followed explicitly.
store the users followed implicitly
store the user’s explicit followers
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 boarrrrrd
Redis Hash is used to store a board’s explicit followers
Redis Set is used to store a board’s explicit unfollowers

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

openredis
redis as a service on AWS
serving over 1000
customers with a single
machine

when things go wrong

the instagrrrrram case
moving from redis to
cassandra: 75% savings on
servers
lesson learnt:
know when redis is not appropriate

the twilio case
credit card hell
lesson learnt:
know what you are doing.
Don't change config on the fly

how teowaki is using redis

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

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

counterrrrrs
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.

Temporarrrrry 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, implementint usage quotas is
trivial
We are controlling our API usage quota with a lua
script following this pattern

bloom filterrrrrs
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 without going to postgresql

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

summarrrrrizing
* 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

If you enjoyed this presentation, please thank
me by registering on http://teowaki.com
It's a site for developers, you can hang around for
free, and I think it's quite cool
<3 <3 <3
Javier Ramírez
@supercoco9
arrrrcamp 2013

Fun with ruby and redis, arrrrcamp edition, javier_ramirez, teowaki

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Fun with ruby and redis, arrrrcamp edition, javier_ramirez, teowaki