Ross Tuck

Redis For The Everyday Developer

ConfooMarch 1st, 2013

Who Am I?

Ross Tuck

Team Lead at IbuildingsCodemonkeyHTTP nutHat guy

@rosstuck

Boring.

http://twitter.com/rosstuck

NoSQL

NoNoSQL

Evaluation

• Created by Salvatore Sanfilippo ( @antirez )• Sponsored by VMware• 4 years old• redis.io

“Redis is an open source, advanced key-value store.”

“It is often referred to as a data structure server...”

Defancypants

Server A Server B

Redis

In-Memory

In-Memory

The Cool Stuff

Fast.

Demo.

Oh wait, it's already done.

120,000~ ops per sec

Flexible.

(optionally)Persistent.

ReplicationPub/Sub

TransactionsScripting

SlicesDices

Makes julienne fries

“Well, Ross, that sounds cool...”

MySQL Redis

+

MySQL+

Redis

4ever

Setup

apt-get install redis-server

Easy but old

http://redis.io/download

PHP Libraries

• 5.3+: Predis

• 5.2: Predis or Rediska

• C Extension: phpredis

• redis-cli

$client = new \Predis\Client();

The Surprise Ending

PHPMySQL

Memcache

PHPMySQL

Memcache

PHPMySQLRedis

It's about 80% cases.

Use Case #1: Caching

Redis has commands.

Commands have parameters.

Think functions.

$client->commandGoesHere($params, $go, $here);

SET

$client->set('ross:mood', 'nervous');

// Later

$client->get('ross:mood'); // returns “nervous”

$client->set('ross:mood', 'nervous');

$client->expire('ross:mood', 5);

// 4 seconds later...

$client->get('ross:mood'); // “nervous”

// 5 seconds later...

$client->get('ross:mood'); // null

$client->set('ross:mood', 'nervous');

$client->expire('ross:mood', 5);

$client->setex('ross:mood', 5, 'nervous');

Great for caching

Ideal for sessions

Use Case #2: Simple Data

Search...

omg cheezburgers in the lunchroomtoday. Better hurry if u want 1!!! ^_^

How do I store this?

key value

key value

homepage_message omg cheezburgers...

key value

homepage_message omg cheezburgers...

tps_reports new cover pages on...

You already know it.

$client->set('home:message', 'cheezburgers...');

$client->get('home:message');

EqualEasier

More Fun

Use Case #3: Hit Counters

increment

$client->incr('page:42:views');

$client->incr('page:42:views');

$client->incr('page:42:views');

// 1

// 2

// 3

Redis is hard ;)

How is this better?

Fast?

redis-benchmark

====== INCR ======

10000 requests completed in 0.08 seconds

50 parallel clients

3 bytes payload

keep alive: 1

100.00% <= 0 milliseconds

119047.62 requests per second

Fast enough.

$client->incr('cookies:eaten');

$client->incrBy('cookies:eaten', 2);

$client->incrByFloat('cookies:eaten', 0.5); version 2.6+

Use Case #4: Latest News

“It is often referred to as a data structure server...”

“...since keys can contain strings, hashes, lists, sets and sorted sets.”

$redis = array();

GenericHashListSetSorted Set

GenericHashListSetSorted Set

// strings and numbers

$redis['ross:mood'] = "happy";

$redis['foo'] = 9;

GenericHashListSetSorted Set

// associative array

$redis['foo']['name'] = 'Bob';

$redis['foo']['age'] = 31;

Objects, forms, records

GenericHashListSetSorted Set

// not associative

$redis['foo'][] = 'zip';

$redis['foo'][] = 'zap';

Lists, stacks, queues

GenericHashListSetSorted Set

// No dupes, no order

shuffle(

array_unique($redis['foo'])

);

Relations, stats, matching

GenericHashListSetSorted Set

// Ordered by *score*

array_unique($redis['foo']);

Curing cancer, world peaceSets but with order or scores

Y U NO STOPY U NO STOP

LISTING THINGSLISTING THINGS

GenericHashListSetSorted Set

GenericHashListSetSorted Set

// Code

$client->lpush('news:latest', 'Aliens Attack!');

// Redis

['Aliens Attack!']

// Redis

['Takei 2016', 'Aliens Attack!']

// 2 hours later...

$client->lpush('news:latest', 'Takei 2016');

// That evening...

$client->lpush('news:latest', 'Eggs = Cancer!');

// Redis

['Eggs = Cancer!', 'Takei 2016', 'Aliens Attack!']

Recap

// Code

$client->lpush('news:latest', 'Aliens Attack!');

$client->lpush('news:latest', 'Takei 2016');

$client->lpush('news:latest', 'Eggs = Cancer!');

// Redis

['Eggs = Cancer!', 'Takei 2016', 'Aliens Attack!']

Getting it back out?

$client->lrange('news:latest', 0, 1);

End Index

Start Index

var_dump(

$client->lrange('news:latest', 0, 1)

);

array(2) {

[0]=> string(14) "Eggs = Cancer!"

[1]=> string(10) "Takei 2016"

}

That's it.Really.

What about size?

$client->lpush('news:latest', 'Free Jetpacks!');

$client->lpush('news:latest', 'Elvis Found!');

$client->lpush('news:latest', 'Takei Wins!');

//...and so on...

ltrim

$client->ltrim('news:latest', 0, 2);

// Only the three latest stories remain!

Cron

or simpler...

$client->lpush('news:latest', 'Cats Leave Euro');

$client->ltrim('news:latest', 0, 2);

Great option for notifications

Use Case #5: Tricksy Caching

SELECT * FROM Articles

INNER JOIN Authors ON (complicated joins)

-- More joins

WHERE (complicated logic)

LIMIT 0, 20

SELECT Articles.id FROM Articles

INNER JOIN Authors ON (complicated joins)

-- More joins

WHERE (complicated logic)

$client->lpush('search:a17f3', $ids);

$client->lrange('search:a17f3', $limit, $offset);

SELECT * FROM Articles

INNER JOIN Authors ON (complicated joins)

-- More joins

WHERE Articles.id IN (1, 2, 3)

Use Case #6: Recently Viewed

GenericHashListSetSorted Set

GenericHashListSetSorted Set

No duplicates

GenericHashListSetSorted Set

Needs to be ordered

Just Right

GenericHashListSetSorted Set

zadd

$client->zadd('mykey', 1, 'mydata');

Any integer

or float

$client->zadd('recent', 1, '/p/first');

$client->zadd('recent', time(), '/p/first');

$client->zadd('recent', 1338020901, '/p/first');

$client->zadd('recent', 1338020902, '/p/second');

$client->zadd('recent', 1338020903, '/p/third');

$client->zadd('recent', 1338020904, '/p/fourth');

Reading it back out?

array(3) {

[0]=> string(8) "/p/first"

[1]=> string(9) "/p/second"

[2]=> string(8) "/p/third"

}

$client->zrange('recent', 0, 2);

$client->zrevrange('recent', 0, 2);

Reverse

array(3) {

[0]=> string(9) "/p/fourth"

[1]=> string(8) "/p/third"

[2]=> string(9) "/p/second"

}

Duplicates?

$client->zadd('recent', 1338020901, '/p/first');

// later...

$client->zadd('recent', 1338020928, '/p/first');

array(3) {

[0]=> string(8) "/p/first"

[1]=> string(9) "/p/fourth"

[2]=> string(8) "/p/third"

}

$client->zrevrange('recent', 0, 2);

Cool.

Other things we can do?

$client->zrangebyscore('recent', $low, $high);

$yesterday = time()-(60*60*24);

$client->zrangebyscore('recent', $yesterday, '+inf');

Intersections

zinterstore

$client->zinterstore('omg', 2, 'recent', 'favorite');

$client->zrange('omg', 0, 4);

Deletion

zrem

zremrangebyscore

$yesterday = time()-(60*60*24);

$client->zremrangebyscore(

'recent', '-inf', $yesterday

);

We can do a lot.

Scores can be anything.

Use Case #7: Sharing Data

Redis

PHP

Node.js Python

• ActionScript• C• C#• C++• Clojure• Common Lisp• Erlang• Fancy• Go• Haskell• haXe• Io

• Java• Lua• Node.js• Objective-C• Perl• PHP• Pure Data• Python• Ruby• Scala• Smalltalk• Tcl

$client = new \Predis\Client();

$client->set('foo', 'bar');

var redis = require("redis");

var client = redis.createClient();

client.get("foo", redis.print);

Step Further...

Pub/Sub

$client->publish('bids:42', '$13.01');

client.on("message", function (channel, message) {

console.log(channel + "= " + message);

});

client.subscribe("bids:42");

// prints “bids:42= $13.01”

Not everydayyet

Use Case #8: Worker Queues

$client->lpush('jobs:pending', 'clear_cache');

$client->lpush('jobs:pending', '{"do":"email", …}');

$client->lpush('jobs:pending', 'job:45');

// worker

$client = new \Predis\Client(array(

'read_write_timeout' => -1

));

do { $job = $client->brpop('jobs:pending', 0);

doJob($job);

} while(true);

This will work.

However...

Things break.

Things break.

Clients break.

Clients break.

Clients crash.

do { $job = $client->brpop('jobs:pending', 0);

doJob($job);

} while(true);

Multiple keys is the redis way.

'jobs:pending'

'jobs:working'

What we need is: blockingrpoplpush

brpoplpush

No, really.

do {

$job = $client->brpoplpush(

'jobs:pending', 'jobs:working', 0

);

doJob($job);

} while(true);

do {

$job = $client->brpoplpush(

'jobs:pending', 'jobs:working', 0

);

if(doJob($job)) {

$client->lrem('jobs:working', 0, $job);

}

} while(true);

Use Case #9: Scripted Commands

Use Case #9: Impressing People

$client->set('jesse', 'dude');

$client->set('chester', 'sweet');

Lua

local first = redis.call('get', KEYS[1]);

local second = redis.call('get', KEYS[2]);

redis.call('set', KEYS[1], second);

redis.call('set', KEYS[2], first);

return {first, second};

var arguments

// jesse: dude

// chester: sweet

EVAL 'local first...' 2 jesse chester

// jesse: sweet

// chester: dude

Eval != Evil

*Offer only appliesin Redis-Land.

Void where pedantic.

Don't over do it.

Reusing scripts?

SCRIPT LOAD 'local first...'

// 591d1b681192f606d8cb658e1e173e771a90e60e

EVAL 'local first...' 2 jesse chester

EVALSHA 591d1... 2 jesse chester

Sweet.

Epilogue

Simple = Powerful

Fun.

Keep it in RAM.

Extensible + Ecosystem

Great docs.Use them.

Bad for the DB?Might be good for Redis.

Bad for the DB?Might be good for Redis.

@svdgraaf

QuickMeme

IAEA Kotaku

Alltheragefaces

http://joind.in/7971