第二十一章 NoSQL（上）
21.1 NoSQL介紹
21.2 memcached介紹
資料結構簡單(k-v)，資料存放在記憶體裡。memcached 不支援持久化，資料落地。每當memcached服務重啟或者重啟伺服器，資料就會丟失。但可以定時來備份來讓資料落地
21.3 安裝memcached
使用yum下載安裝
yum -y install memcached
想下載最新版本可以去官網上下載原始碼包，由於memcached是基於libevent，因此，當你yum安裝memcached時就已經安裝libevent
啟動memcached服務
systemctl start memcached.service
啟動引數-u 指定執行memcached服務的使用者-p 執行監聽埠-m 指定記憶體大小 單位M-c 指定最大併發數
啟動引數配置檔案在/etc/sysconfig/memcached
更改啟動引數配置檔案
vim /etc/sysconfig/memcachedPORT="11211" ##埠
USER="memcached" ##使用者
MAXCONN="1024" ##最大併發數
CACHESIZE="64" ##分配記憶體大小
OPTIONS=""21.4 檢視memcached狀態
使用memcached-tool工具來檢視memcached狀態
memcached-tool 127.0.0.1:11211 stats
#127.0.0.1:11211 Field Value accepting_conns 1 auth_cmds 0 auth_errors 0 bytes 0 bytes_read 14 bytes_written 1024 cas_badval 0 cas_hits 0 cas_misses 0 cmd_flush 0 cmd_get 0 cmd_set 0 cmd_touch 0 conn_yields 0 connection_structures 11 curr_connections 10 curr_items 0 decr_hits 0 decr_misses 0 delete_hits 0 delete_misses 0 evicted_unfetched 0 evictions 0 expired_unfetched 0 get_hits 0 get_misses 0 hash_bytes 524288 hash_is_expanding 0 hash_power_level 16 incr_hits 0 incr_misses 0 libevent 2.0.21-stable limit_maxbytes 67108864 listen_disabled_num 0 pid 1275 pointer_size 64 reclaimed 0 reserved_fds 20 rusage_system 0.039859 rusage_user 0.028470 threads 4 time 1534201319 total_connections 12 total_items 0 touch_hits 0 touch_misses 0 uptime 1050 version 1.4.15
在生產環境中要留意 curr_items暫存的專案 cmd_get表示總的get次數，get_hits表示get的總命中次數，命中率 = get_hits/cmd_get。
使用nc命令來檢視memcached狀態
yum -y install nc
echo stats |nc 127.0.0.1 11211
STAT pid 1275
STAT uptime 2058
STAT time 1534202327
STAT version 1.4.15
STAT libevent 2.0.21-stable
STAT pointer_size 64
STAT rusage_user 0.050910
STAT rusage_system 0.070002
STAT curr_connections 10
STAT total_connections 13
STAT connection_structures 11
STAT reserved_fds 20
STAT cmd_get 0
STAT cmd_set 0
STAT cmd_flush 0
STAT cmd_touch 0
STAT get_hits 0
STAT get_misses 0
STAT delete_misses 0
STAT delete_hits 0
STAT incr_misses 0
STAT incr_hits 0
STAT decr_misses 0
STAT decr_hits 0
STAT cas_misses 0
STAT cas_hits 0
STAT cas_badval 0
STAT touch_hits 0
STAT touch_misses 0
STAT auth_cmds 0
STAT auth_errors 0
STAT bytes_read 20
STAT bytes_written 2053
STAT limit_maxbytes 67108864
STAT accepting_conns 1
STAT listen_disabled_num 0
STAT threads 4
STAT conn_yields 0
STAT hash_power_level 16
STAT hash_bytes 524288
STAT hash_is_expanding 0
STAT bytes 0
STAT curr_items 0
STAT total_items 0
STAT expired_unfetched 0
STAT evicted_unfetched 0
STAT evictions 0
STAT reclaimed 0
END使用memstats命令來檢視memcached狀態
先安裝 libmemcached
yum -y install libmemcached
memstat --servers=127.0.0.1:11211
Server: 127.0.0.1 (11211)
pid: 1275
uptime: 2277
time: 1534202546
version: 1.4.15
libevent: 2.0.21-stable
pointer_size: 64
rusage_user: 0.056080
rusage_system: 0.077110
curr_connections: 10
total_connections: 14
connection_structures: 11
reserved_fds: 20
cmd_get: 0
cmd_set: 0
cmd_flush: 0
cmd_touch: 0
get_hits: 0
get_misses: 0
delete_misses: 0
delete_hits: 0
incr_misses: 0
incr_hits: 0
decr_misses: 0
decr_hits: 0
cas_misses: 0
cas_hits: 0
cas_badval: 0
touch_hits: 0
touch_misses: 0
auth_cmds: 0
auth_errors: 0
bytes_read: 37
bytes_written: 3098
limit_maxbytes: 67108864
accepting_conns: 1
listen_disabled_num: 0
threads: 4
conn_yields: 0
hash_power_level: 16
hash_bytes: 524288
hash_is_expanding: 0
bytes: 0
curr_items: 0
total_items: 0
expired_unfetched: 0
evicted_unfetched: 0
evictions: 0
reclaimed: 0總結三種檢視memcache狀態命令
memcached-tool IP:埠 statsecho stats |nc IP 埠memstat --servers=IP:埠
21.5 memcached命令列
使用Telnet進入memcached
telnet 127.0.0.1 11211
退出Telnet按Ctrl+]再輸入quit撤銷按Ctrl+退格鍵
新增鍵
set key1 0 100 2 ## 0為標記 100為儲存時間 2為2位數abSTORED
獲得鍵對應的值
get key1
VALUE key1 0 2
ab
END替換值
replace key1 0 1000 3 ##replace和set一樣也要輸入<flags> <exptime> <bytes>
123
STORED刪除鍵
delete key1
DELETED
21.6 memcached資料匯出和匯入
由於memcached在重啟服務或者重啟機器就會把資料丟掉，因此需要把資料進行備份。
使用memcached-tool命令把資料匯出
格式：memcached-tool IP:埠 dump > 備份檔案
vim data.txt 更改時間戳
檢視之前儲存的資料
通過時間戳找出對應的時間。因為我們裝置設定資料的過期時間為0，永不過期。但是匯出資料就會把建立資料的時間為過期時間，因此要把時間改一改，不然匯入資料就會出問題
21.7 php連線memcached
進入src目錄並下載解壓memcache
cd /usr/local/src/
wget http://www.apelearn.com/bbs/data/attachment/forum/memcache-2.2.3.tgz
tar zxvf memcache-2.2.3.tgz
進入memcache目錄下並生成configure檔案
cd memcache-2.2.3
/usr/local/php-fpm/bin/phpize這裡是缺少autoconf導致的因此安裝autoconf再來phpize
yum install -y autoconf/usr/local/php-fpm/bin/phpize用來生成configure檔案
初始化
./configure --with-php-config=/usr/local/php-fpm/bin/php-config
make && make install
檢視模組
vim /usr/local/php/etc/php.iniextension=memcache.so
測試
下載一個php的測試頁面看是否支援php來操作memcache
https://coding.net/u/aminglinux/p/yuanke_centos7/git/blob/master/21NOSQL/1.php
curl www.apelearn.com/study_v2/.memcache.txt > 1.php 2>/dev/null
21.8 memcached中儲存session
vim /usr/local/php-fpm/etc/php.ini
註釋掉 session.save_handler = files
它表示session以檔案的形式存在tmp目錄下
編輯php-fpm.conf對應的pool
php_value[session.save_handler] = memcache
php_value[session.save_path] = "tcp://192.168.93.128:11211"
測試
下載一個php測試頁面看memcache是否儲存了session
程式碼內容在https://coding.net/u/aminglinux/p/yuanke_centos7/git/blob/master/21NOSQL/session.php
wget http://study.lishiming.net/.mem_se.txt
cp .mem_se.txt /var/wwwroot/aming.com/index.php
