Memcached Cache Database

MemcachedCache Database

1th ChapterWhat isMemcache?

Open source software for dynamic Web applications to reduce the load on the database, by caching data and objects in memory to reduce the number of service databases , thereby increasing the speed of website access , Working mechanism is to open up a space in memory , build a hash table memcached self-manage these hash table

2nd ChapterWhy use a cached database?

1.      mysql        --- data is stored on disk , Io slower ---- Data Warehouse Storage Select MySQL This disk database

2. memcached--- data in memory , io fast --- high concurrency , business volume should choose memcache this memory data

3rd ChapterCache Database Usage Scenarios:

1. as a database cache --- data can be cached in memory when MySQL cannot withstand large concurrent requests

2. session sharing --- as long as you log in once , you do not need to log in again

4th Chapter Cookiesand theSession

website program to determine user login information , the first odd way : The server in your browser to write a cookie, this cookie contains your user name and login information , because cookies are stored in a local browser , so third-party tools can easily steal privacy information from cookies, the session emerged

4.1At the beginning:

cookies= content ( user name , login information )

4.2after improvement:

Cookies=session ID

session= user name , login information

General enterprise application is cookies+session

5th Chapter Memcachedsub-deployment cache cluster

Memcached is inherently unsupported for distributed clusters and can only be deployed through programs to support sub-deployment storage

5.1 memcachedcharacteristics of distributed cache clusters:

all MC server memory content is different, these server content together close to the database capacity , such as 1t database , a cache database memory is not so large and therefore divided into ten servers

5.2NormalHashalgorithm:

The Ongoinghash algorithm on the load balancer of the client program or MC, so that the same content is assigned to a MC server , This algorithm can bring a lot of data flow to the node outage , which can cause avalanche effect easily .

5.3ConsistencyHashalgorithm:

by generating a hash circle , data is matched to the nearest server by the clockwise distance , which minimizes the flow of node data to the node outage.

6th ChapterDeploymentMemcachedService: 1.1Installing server-side software:

[Email protected] ~]# yum-y install memcached

1.1.1ViewMemcachedconfiguration file

[Email protected] ~]# cat/etc/sysconfig/memcached

Port= "11211" listening port

User= "memcached" named user

Maxconn= "1024x768" Concurrent access number

Cachesize= the size of the memory

Options= ""

1.2StartMemcacheService

[[email protected] ~]#/etc/init.d/memcached start

Starting memcached: [OK]

1.3writing data to the cache database

[[email protected] ~]# printf "set key008 0 0 10\r\noldboy1234\r\n" |nc 127.0.0.1 11211

STORED writing data successfully

key008--- the name of the data

0---

0 ---time out , the data will not be accessible over this time

The--- represents the number of characters written to the data , where oldboy1234 is a number of characters, so 10

1.4view data in a database

[[email protected] ~]# printf "Get key008\r\n" |nc 127.0.0.1 11211

VALUE key008 0 10

oldboy1234

END

1.5Delete Data

[[email protected] ~]# printf "Delete key008\r\n" |nc 127.0.0.1 11211

DELETED

[[email protected] ~]# printf "Get key008\r\n" |nc 127.0.0.1 11211

END

7th ChapterClient Deploymentmemcache:2.1installationMemcache

1089 CD memcache-2.2.5

1090/application/php/bin/phpize

1091./configure--enable-memcache--with-php-config=/application/php/bin/php-config--with-zlib-dir

1092 make && make install

1093 echo $?

2.1.1Check directory exists after executing commandMemcache.socan be

[Email protected] memcache-2.2.5]# ll/application/php-5.6.32/lib/php/extensions/no-debug-non-zts-20131226/

Total 256

-rwxr-xr-x 1 root root 260643 Feb 21:21 memcache.so

2.1.2IncreasePhpinMemcacheModule

[[Email protected] memcache-2.2.5]# sed ' $a extension=memcache.so '/application/php/lib/php.ini-i.ori

[[email protected] memcache-2.2.5]# pkill PHP

[Email protected] memcache-2.2.5]#/application/php/sbin/php-fpm-t

[19-feb-2018 21:30:59] Notice:configuration file/application/php-5.5.32/etc/php-fpm.conf Test is successful

[Email protected] memcache-2.2.5]#/APPLICATION/PHP/SBIN/PHP-FPM

[Email protected] memcache-2.2.5]#/application/php/sbin/php-fpm-m |grep memcache

Memcache Check if PHP has added memcache module functionality

2.2 PHPCode Testing: 2.2.1in the Site directoryBlogwrite a test file in:

Cat >>/application/nginx/html/blog/mc.php<< ' EOF '
<?php
$memcache = new Memcache;
$memcache->connect ('10.0.0.21', 11211) or Die ("Could not Connect");
$memcache->set (' key20180314 ', ' Hello,world ');
$get _value = $memcache->get (' key20180314 ');
echo $get _value;
?>
Eof

2.2.2TestWebpage access is normal

1.1.1check the presence of data on the cache server:

[[email protected] ~]# printf "Get key20180314\r\n" |nc 10.0.0.21 11211

VALUE key20180314 0 11

Hello,world

END

8th Chapter WebManagementMemcached:

Tar XF memadmin-1.0.12.tar.gz-c/application/nginx/html/blog/

Browser Access http://blog.etiantian.org/memadmin

Host: option to fill in the IP address of the cache server

9th ChaptermakeMemcachedCacheWordpressBlog Data: 1.1putobject-cache.phpProgram files are uploaded to the site Directory

cd/application/nginx/html/blog/wp-content/

Rz

[email protected] wp-content]# LL

Total 28

-rw-r--r--1 Nobody 65534 9 index.php

-rw-r--r--1 root root 10112 Mar 12:05 object-cache.php

1.2Modify the file in theIpAddress

grep 127.0.0.1 object-cache.php

Sed-i ' s#127.0.0.1#10.0.0.21# ' object-cache.php

1.2.1Log in to the website to send a blog:

1.1.1LoginMemcache Webinterface to check:Cache Post Success

10th Chapter Memcached SessionSession Sharing:

method One : through the program implementation , WEB01 only need to write to memcache session,web02 read from memcache Session, as normal data read and write , more Universal

method Two : through php configuration file , PHP default session stored in the file , modified to be stored in the memcached

Sed ' s#session.save_handler = Files#session.save_handler = memcache# '/application/php/lib/php.ini-i

Sed ' $a session.save_path = "tcp://127.0.0.1:11211" '/application/php/lib/php.ini-i

/application/php/sbin/php-fpm-t

Pkill PHP

/application/php/sbin/php-fpm

using this function , you need to use the session function of PHP

Memcached Cache Database