memcached may 29

Designing and ImplementingScalable Applications with Memcached and MySQL

Farhan "Frank" MashraqiDirector of Business Operations and Technical Strategy - Fotolog Inc

Monty TaylorSenior Consultant - Sun Microsystems

Jimmy GuerreroSr Product Marketing Manager - Sun Microsystems, Database Group

• Sun – MySQL Overview

• Technical Introduction

• Architectures

• Use Cases

• Solutions

• Next Steps plus Q & A

MySQL Helps Sun...

• Grow in a $15B database market

• Reach new customers

• Position its offerings for Web companies

• Deliver innovation to community & customers

• Complete its software platform offerings

Sun Helps MySQL…

• Expand market reach and revenue opportunities

• Enhance enterprise appeal with global services

• Enhance performance and integration

• Resources for accelerated growth

Sun Acquires MySQL

About MySQL

Leadership * Innovation * Open * Ubiquitous

• 12 years old

• 400+ employees

• 750 partners

• 60K downloads/day

• Customers across every major

operating system, hardware

vendor, geography, industry,

and application type

Established & Emerging Companies

craigslist

Web 2.0

Enterprise 2.0

Telecom

OEM & ISV

Technical Introduction

mtaylor@mysql.com

“Cache is King”

• Browser Cache

• Web Server Cache

• Memcached Cache

• MySQL Database Cache

• Disk Storage

What is Memcached?

“A high-performance, distributed memory object caching

system, generic in nature, but intended for use in speeding up

dynamic web applications by alleviating database load” *

* http://www.socialtext.net/memcached/index.cgi?faq

• Created by Danga Interactive to speed up LiveJournal’s 20

million+ dynamic page views per day for 1 million+ users

• Significantly dropped database load, delivering faster page

loads, better resource utilization, and faster access to

databases

• Perfect for dynamic sites that generate high database load

• Used by Facebook, YouTube, Wikipedia, others!

What is Memcached?

• Runs wherever RAM is available

– Application, Web, Database or dedicated memcached servers

– Low CPU utilization

– Multiple operating systems and architectures supported

• Open Source - Community Driven

• Memcached Server is licensed under BSD

• Current version is 1.2.x series

– http://www.danga.com/memcached/download.bml

• Various Client APIs and libraries available

– Perl, Python, Ruby, Java, C#, C, Lua, MySQL, more….

– http://www.danga.com/memcached/apis.bml

Why Use Memcached With MySQL?

• Enables massive scale-out of dynamic web-sites

• Faster page loads

• Allows for more efficient use of existing database resources

• Can easily utilize idle computing resources

• Dozens to hundreds of nodes can be supported in a

memcached cluster

• No interconnect or proprietary networking required

• Extensible and customizable

How Does Memcached Work?

Hash Function

• A hash is a procedure for turning data into a small integer that serves as an index into an array

• Speeds up table lookup or data comparison tasks

Memcached

• Two-stage hash, like a giant hash table looking up key = value pairs

• Client hashes the key against a list of servers

• When the server is identified, the client sends its request

• Server performs a hash key lookup for the actual data

Memcached Server

• Slab allocator

– Memory permanently allocated

– Classes created by chunk size

– Cannot reassign slab pages

• Libevent based

• Simple protocol (no xml)

• Server has internal hash table

• Servers know nothing about each other

Memcached Server• Limits

– Key size (250 bytes)

– Data size (under 1 MB)

– 32bit/64bit (maximum size of process)

– Maxbytes (limits item cache)

• LRU

– Least recently accessed items are cycled out

– One LRU exists per “slab class”

– LRU “evictions” need not be common

• Threads

– New in version 1.2

– Big instances (16 GB+)

– Large multiget requests

Memcached Commands

• set/get/replace

• append/prepend

• increment/decrement

• cas (compare and swap atomic)

• stats (detail)

Memcached Clients

• Client hashes key to server list (distribution)

• Serializes the object

• Compresses data

• “Consistent hashing” client

• Other things to know about memcached…

– Dumping and loading data

– Redundancy

– Failover

– Authentication

Basic Memcached Example

Client X

1) set key “foo” with value “seattle”

2) hashes the key against server list

3) Server B is selected

4) connects to Server B and sets key

Client Z

5) get key “foo”

6) connects to Server B

7) requests “foo” and gets value “seattle”

hash server list

select server

connect

set key value

get key

connect

get value

key = valuefoo = seattle

Memcached vs MySQL Query Cache

• Distributed• Unlimited Size• Generic Data Storage• No Direct Invalidation• Maximum 1 MB

• Centralized (Single Server)• Limited by maximum addressable space of mysqld• Database data only• Invalidated by any write on tables used in SELECT• Configurable per item

ms ms ms

Memcached vs MySQL Cluster

• Distributed• Unlimited Size• Generic Data Storage• No Direct Invalidation• Maximum 1 MB

• Distributed• Limited Size• Datatype storage limits• No invalidation (DELETE instead)• HA and Redundant• SQL and NDB API support

ms ms ms

Application Nodes(NDB API and/or MySQL Server)

Data Nodes

ManagementNode

NDB Storage Engine

Architectures

Memcached & MySQL

Web Servers

Application Servers

MemcachedServers

MySQL Server

MemcachedClients mc mc

read write

cache update

On-Demand Read Scalability for MySQL

MySQL Replication

• Designed for on-demand read scalability

• Cost-effective alternative to Scale-Up

• Asynchronous replication

• Statement or row-level replication support

• No special networking components

• Fully-supported via MySQL Enterprise subscription

• Enterprise Monitor discovers and monitors replication

topologies

MySQL Replication – Scale-Out

MySQLReplication

writes

MySQL ReplicationWeb/AppServers

Memcached & MySQL Replication

Application Servers &

Memcached Clients

MySQLSlaves

MySQLMaster

read from cache write

MemcachedServers ms

cache update

MySQLReplication

read from slave

Sharding - Application Partitioning

Cust_id 1-999

Cust_id 1000-1999

Cust_id 2000-2999

Web/AppServers

Sharding Architecture

Memcached, Sharding & MySQL Replication

cache update

MySQLReplication

msms msms msms

cache update

MySQLReplication

msms msms

shard 1 (cust 1-999) shard 2 (cust 1000-1999)

read from cache

mc mc mc

read from slave

read from cache

read from slave

read from cache

Use Cases

Farhan "Frank" MashraqiDirector of Business Operations and Technical Strategy

Fotolog Inc

fmashraqi@fotolog.com

Fotolog Introduction• World’s largest photo blogging community

– > 18 million members

– > 155 million page views

• Ranked top 57 site

– 13th before Alexa changed ranking algorithm

Memcached @ Fotolog

• 51 instances on 21 servers

• ~254G available to memcached servers

• ~175G in use

• Cache everything that is slow to query, fetch or

calculate

Memcached Use Cases

• Non-deterministic cache: Classic memcached model

• “State” cache

• Deterministic cache

• Proactive cache

• Replacement/add-on for file system cache

• Partial page cache

• Application-based memcached replication

Non-Deterministic Cache:

Classic Memcached Model

• Check memcached, check database, then populate memcached

• Previously using classic implementation: – App servers running memcached on “spare” memory

• 90% CPU usage

• Memory garbage collected nearly once a minute

• Experienced blocking on memcached on app servers

• 45 memcached instances dedicated to non-deterministic cache– Each instance (on average):

• ~440 gets per second

• ~40 sets per second

• ~11 gets/set

Non-Deterministic Cache:

Classic Memcached Model

• Ideal for:

– Caching objects that are to be queried several times

– Replacement for MySQL’s query cache

– Caching relationships and other lists

– Slow data that’s used across many pages

– Don’t cache if its more taxing to cache than you’ll save

– Tag clouds and auto-suggest lists

State Caching

• “Who’s online?”

• ~9G dedicated

• Multiple instances

• Ideal for caching:

– Sessions

– Current state of users

• Especially for IM applications

Deterministic Cache

• Memcached has what database has…read scalability

• Multiple dedicated cache pools

• Cache has to be populated when the site “starts”– Maintained by application from that point onwards

– ~ 90,000 gets / second across cache cluster

– ~ 300 sets / second

– get/set ratio of ~ 300

• Ideal for caching:– Heavily accessed data/objects/lists

– User credentials

– User profiles

– User preferences

– Active media belonging to users

– Outsourcing logins to memcached

Proactive Caching

• “It’s magically there”

• Fun with binlogs

– Easier to implement for UPDATEs

– A little bit of extra logic required for INSERTs

– DELETEs can be honored easily

• Ideal for

– Pre-Populating Cache: Keeping memcached updated

minimizes calls to database if object not present

– “Warm up” cache in cases of cross data-center replication

Proactive Caching

• Fun with UDFs

• Memcached UDFs for MySQL

– Major contributing author: Patrick Galbraith

– Allows you to manage memcached when used with triggers.

– Implemented using libmemcached

– Compatible with all versions of MySQL

– Examples:

• memc_servers_set()

• memc_set()

• memc_get()

• memc_delete()

• memc_increment()

• memc_decrement()

• memc_replace()

• Complete list available at

– http://tangent.org/586/Memcached_Functions_for_MySQL.html

Proactive Caching

• Fun with blackhole– thanks to Brian Aker

• Create a blackhole table– CREATE TABLE blackhole_table … ENGINE=blackhole;

• Replicate this table

• Add triggers at right places.

• Example: Make multiple INSERTs– INSERT <real_insert>;

– INSERT INTO blackhole_table VALUES (memc_set(id));

• Benefits– Actual data is not sent to slave disks

– Not CPU intensive for slaves

Add-on/Replacement for NFS File System Cache

• NFS has a significant overhead

– File system cache for NFS systems not enough

• Ideal for caching:

– XML files

– Small size media stored on NFS mounts

Partial Page Caching

• Certain partial page elements are…

– Very costly to generate

– Shared among many pages

– Viewed several times

• Examples:

– Top users within a region

– Popular photo lists

– Featured users

• Once generated these can be shared

Application-Based Memcached Replication

• Ideal for deterministic cache cluster

• Redundancy

– Application writes to multiple memcached pools

• High availability

– Take node out of rotation

Memcached Wishlist

• “Built-in” replication

• Integration with binary logs

• A “hybrid” storage engine?

• Production support

– Now fulfilled thanks to Sun/MySQL

Solutions

Jimmy GuerreroSr Product Marketing Manager

Sun Microsystems - Database Group

jimmy@mysql.com

Memcached for MySQL

• Support is built into your MySQL Enterprise subscription

http://www.mysql.com/products/enterprise/memcached.html

• MySQL Enterprise– 24x7 Production Support

– Enterprise Monitor

– MySQL Enterprise Server

– Additional Add-ons Available

• MySQL Professional Services– MySQL Scale, High-Availability and Replication Jumpstart

MySQL Enterprise

Deploy and monitor an unlimited number of servers for the

price of a single CPU of Oracle

MySQL Enterprise

MySQLEnterpriseServer

MySQLEnterpriseMonitor

24x7ProductionSupport

MySQLEnterpriseUnlimited

Enterprise database and monitoring software, plus

production support delivered in an annual subscription

Why MySQL Enterprise?

• Deliver on SLAs

• Increase availability

• Optimize performance

• Effectively monitor scale-out environments

• Faster time to launch

• Develop & deliver on proven open source components

• Keep costs predictable

MySQL Enterprise Monitor

• Consolidated view of entire MySQL environment

• Auto discovery of MySQL Servers & replication topologies

• Over 100 customizable rules for monitoring and alerting

• Identifies problems before they occur

• Reduces risk of downtime

• Improve delivery of SLAs

• Scale-out with less DBAs

Why Memcached with MySQL?

• Enables massive scale-out of dynamic web-sites

• Faster page loads

• Allows for more efficient use of existing database resources

• Can easily utilize idle computing resources

• Dozens to hundreds of nodes can be supported in a

memcached cluster

• No interconnect or proprietary networking required

• Extensible and customizable

Next Steps

Memcached for MySQL -

Whitepapers - http://www.mysql.com/why-mysql/white-papers/

• “Designing and Implementing Scalable Applications with Memcached and MySQL”

• “How MySQL Powers Web 2.0”• “Enabling Enterprise 2.0 with MySQL”

Documentation -

http://dev.mysql.com/doc/refman/5.1/en/ha-memcached.html

Discussion Forum - http://forums.mysql.com/list.php?150

Miscellaneous Resources -

Questions?

Farhan "Frank" MashraqiDirector of Business Operations and Technical Strategy - Fotolog Inc

Jimmy GuerreroSr Product Marketing Manager - Sun Microsystems, Database Group

memcached may 29

Documents

Transcript of memcached may 29

Dk Memcached Hadoop

29 May 2015.pdf

2014 21 laportada 29 may 2014

29 may 2014 e paper

Memcached 源码剖析笔记 - files.cppblog.comfiles.cppblog.com/xguru/Memcached.pdf · Memcached 源码剖析笔记 Xguru Memcached 是一个自由、源码开放、高性能、分布式

Cotonou , Benin 24-29 May 2010

Redis memcached pdf

May 29 El Clarín

NoordKaap 29 May 2013

MySQL Memcached Grazr

memcached proxy server development and operation

May 29, 2013

떠먹여주는 Memcached 1

Correo Canadiense • May 29, 2015

Memcached 剖析

PHP i memcached, zaawansowane przypadki użycia

29 may 2016

Web, кэширование и memcached

Memcached vs redis

29 may 2021 dammy - mcu.ac.in