PHP at Scale:Knowing enough to be dangerous!

Oleksii PetrovSkelia Ukraine / ETWater

Who am ISystem ArchitectTeam LeadPHP Developer

Find me on@alexhelkar

alexhelkar

https://github.com/alexhelkar

What does it mean"to scale"?

Does it mean?

Or does it mean?

Often it means

"To scale"Improve system metrics

without changing thesystem*

* (dramaticaly)

Scale roadmap is predefinedby your stack and software architecture

Let's go!

PerformanceStory

PHP 7 factsisset 1.55 times faster than array_key_existsis_file 26 times faster than file_existssingle quotes slower that double quotesinstanceof faster is_aetc.

Code performance?

Blackfire.io & Symfony Blog

Current results:Total request time: 18.4 msfile_exists called: 7 timesExec. time for file_exists: 460 µs Expected results:Exec/ time: ~17.6 µsTotal request time: ~18.3996 ms

PHP lang performance

...овно?

OR

...амно?

Why a system isslow?

Because ofDatabase!

Scaling strategiesCachingQueueingReads/Writes SplitingSharding

Caching

Typical Request Flow

DB Cache

Application Cache

Web Cache

Cache: Rule of thumb

IF Application is SLOWEnable Caching

IF Application has GLITCHESDisable Caching

Queueing

Queue as The Equalizer

Queue as The Equalizer

Problems?

Delays

Queue as Load Balancer

Problems?

Unboundedbuffers!

Read/Write Splitting

Master-Slave replicationasync/semi-sync

Writes

Reads Reads

Problems?

Replication lag

Galera Replicationaka sync replication

Problems?

WritesPerformance

What is IoT?

IoT is like

CanvasREST APIWeather DataAvg. Request Size 325b

Data Sample{ "deviceId": 231, "lat":"45.22838254", "lng":"-114.23725403", "timestamp":1459509524, "temperature":2.99, "precipProbability":0.386, "humidity":0.055, "pressure":1035.617}

Load GeneratorYandex Tank

TasksCreate platform setupGather performance metricsCalculate budgets

Plan 1: 86k req/day (1 rps)

Plan 2: 8.64M req/day (100 rps)

Setup: 20$

Response Time

Limitation

Same Setup: 200rps

Why 3 databaseservers?

Probability?

Head: 50% | Tails: 50%

Probability of 2 consecutive Heads?

25%

Probability of 3 consecutive Heads?

12.5% 0.5^3

Servers reliability

1 Server 99%

10 Servers 90.4%

100 Servers 36.6%

Distributed System

High Availability

Any

should consider

Plan 4: 43.2M req/day (500rps)

Setup Variant 1: 380$

Quantiles

Setup Variant 2: 150$

Quantiles

Mircoservices230 Reasons to choose

380$ - 150$ = 230$

Plan 5: 84.6M req/day (1k rps)

Plan 5: 84.6M req/day (1k rps)

Plan 6: 432M req/day (5k rps)

Started to thinkabout bulk inserts?

Plan 7: 1.26B req/day (15k rps)

Quantiles

TCP/IP

TCP Flow

Packets Rate

Packets Rate

1 Request

15k Requests

~10 Packets

~15k Packets

Load Balancer Trick

Load Balancer Trick

Load Balancer Trick

Load Balancer Trick

Why?

Load Balancer Trick

75k pack.

75k pack.

LB Recieved: 150k packets

Plan 7: 50000 req/sec

CommodityHardware

Commodity Hardware

$5 Server 1 CPU

20 CPU $100 Server

$640 Server

c4.8xlarge: $1222.750/monthly

DNS Load Distribution

DNS Load Distribution

DNS Cache

Rule of Thumb: Add LB

What if?

Floating IP

Sharding?Last Resort

Mysql: Manual Sharding

Mysql: Fabric (pre-alpha)<?php

$mysqli = new mysqli("myapp", "user", "password", "database");

mysqlnd_ms_fabric_select_shard($mysqli, "test.fabrictest", 10);$mysqli->query("INSERT INTO fabrictest(id) VALUES (10)");

mysqlnd_ms_fabric_select_shard($mysqli, "test.fabrictest", 10);$mysqli->query("SELECT id FROM test WHERE id = 10");

http://php.net/manual/ru/mysqlnd-ms.quickstart.mysql_fabric.php

MariaDB: Spider

Mysql Cluster (NDB)

MongoDB Sharding

Apache Cassandra

RabbitMQHits 1 Million Messages Per

Second. 32 machines

https://blog.pivotal.io/pivotal/products/rabbitmq-hits-one-million-messages-per-

second-on-google-compute-engine

Apache Kafka2 Million Writes Per Second

3 machines

https://engineering.linkedin.com/kafka/benchmarking-apache-kafka-2-million-writes-

second-three-cheap-machines

Instead SummaryScalability as afterwords doesn't workDatabase is not a queueDatabase is not a lock systemRedis is not a queueLoad balancers as a mustLinear disk writes winsPerfomance in PHP is done by everything except PHPBeing distributed is freaking hard

Questions?

Find me on@alexhelkar

alexhelkar

https://github.com/alexhelkar