Redis for the Everyday Developer

Redis For The
Everyday Developer

Ross Tuck
Confoo
March 1st, 2013

Team Lead at Ibuildings
Codemonkey
HTTP nut
Hat guy

• 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...”

Redis

Server A Server B

Replication
Pub/Sub
Transactions
Scripting
Slices
Dices
Makes julienne fries

“Well, Ross, that sounds cool...”

apt-get install redis-server

Easy but old

PHP Libraries

• 5.3+: Predis

• 5.2: Predis or Rediska

• C Extension: phpredis

• redis-cli

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

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

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

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

// 4 seconds later...
$client->get('ross:mood'); // “nervous”

// 5 seconds later...
$client->get('ross:mood'); // null

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

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

Search...

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

How do I store this?

key value
homepage_message omg cheezburgers...

key value
homepage_message omg cheezburgers...
tps_reports new cover pages on...

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

$client->incr('page:42:views'); // 1

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

$client->incr('cookies:eaten');
$client->incrBy('cookies:eaten', 2);
$client->incrByFloat('cookies:eaten', 0.5); version 2.6+

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

Generic
Hash
List
Set
Sorted Set

Generic
Hash // strings and numbers
List $redis['ross:mood'] = "happy";
Set $redis['foo'] = 9;

Sorted Set

Generic
Hash // associative array
List $redis['foo']['name'] = 'Bob';
$redis['foo']['age'] = 31;
Set
Sorted Set
Objects, forms, records

Generic
Hash // not associative
List $redis['foo'][] = 'zip';
Set $redis['foo'][] = 'zap';

Sorted Set
Lists, stacks, queues

Generic
// No dupes, no order
Hash
shuffle(
List
array_unique($redis['foo'])
Set );
Sorted Set
Relations, stats, matching

Generic
Hash // Ordered by *score*
List array_unique($redis['foo']);
Set
Sorted Set
Curing cancer, world peace
Sets but with order or scores

Y U NO STOP

LISTING THINGS

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

// Redis
['Aliens Attack!']

// 2 hours later...
$client->lpush('news:latest', 'Takei 2016');

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

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

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

// 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!']

Start Index

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

En d Index

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

array(2) {
[0]=> string(14) "Eggs = Cancer!"
[1]=> string(10) "Takei 2016"
}

$client->lpush('news:latest', 'Free Jetpacks!');
$client->lpush('news:latest', 'Elvis Found!');
$client->lpush('news:latest', 'Takei Wins!');
//...and so on...

$client->ltrim('news:latest', 0, 2);
// Only the three latest stories remain!

$client->lpush('news:latest', 'Cats Leave Euro');
$client->ltrim('news:latest', 0, 2);

Great option for notifications

SELECT * FROM Articles
INNER JOIN Authors ON (complicated joins)
-- More joins
WHERE (complicated logic)
LIMIT 0, 20

SELECT Articles.id FROM Articles
-- More joins
WHERE (complicated logic)

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

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

SELECT * FROM Articles
-- More joins
WHERE Articles.id IN (1, 2, 3)

Generic
Hash
List No duplicates
Set
Sorted Set

Generic
Hash
List
Set Needs to be ordered
Sorted Set

Generic
Hash
List
Set
Sorted Set Just Right

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

Any integer
t
or floa

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

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

$client->zadd('recent', 1338020902, '/p/second');
$client->zadd('recent', 1338020903, '/p/third');
$client->zadd('recent', 1338020904, '/p/fourth');

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

array(3) {
[0]=> string(8) "/p/first"
[1]=> string(9) "/p/second"
[2]=> string(8) "/p/third"
}

Reverse

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

array(3) {
[0]=> string(9) "/p/fourth"
[2]=> string(9) "/p/second"
}


// later...

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

array(3) {
[0]=> string(8) "/p/first"
[1]=> string(9) "/p/fourth"
}

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

$yesterday = time()-(60*60*24);
$client->zrangebyscore('recent', $yesterday, '+inf');

$client->zinterstore('omg', 2, 'recent', 'favorite');
$client->zrange('omg', 0, 4);

$yesterday = time()-(60*60*24);
$client->zremrangebyscore(
'recent', '-inf', $yesterday
);

PHP

Redis

Node.js Python

• ActionScript • Java
• C • Lua
• C# • Node.js
• C++ • Objective-C
• Clojure • Perl
• Common Lisp • PHP
• Erlang • Pure Data
• Fancy • Python
• Go • Ruby
• Haskell • Scala
• haXe • Smalltalk
• Io • Tcl

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

var redis = require("redis");
var client = redis.createClient();

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

$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”

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

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

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

// worker
$client = new PredisClient(array(
'read_write_timeout' => -1
));

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

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

Multiple keys is the redis way.

What we need is: blocking
rpop
lpush

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');

var arguments

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};

// jesse: dude
// chester: sweet

EVAL 'local first...' 2 jesse chester

// jesse: sweet
// chester: dude

Eval != Evil

*Offer only applies
in Redis-Land.
.
Void where pedantic

SCRIPT LOAD 'local first...'
// 591d1b681192f606d8cb658e1e173e771a90e60e

EVAL 'local first...' 2 jesse chester

EVALSHA 591d1... 2 jesse chester

Bad for the DB?
Might be good for Redis.

IAEA Kotaku

@svdgraaf

Alltheragefaces

QuickMeme

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