PHP: Grundlegende Verwendung

Grundlegende Verwendung

Beispiel #1 Memcache Beispiele

In diesem Beispiel wird ein Objekt im Cache gespeichert und anschließend wieder ausgelesen. Objekte und andere nicht-skalare Typen werden vor dem Speichern serialisiert. Somit ist es nicht möglich, Ressourcen im Cache zu speichern.

<?php

$memcache = new Memcache;
$memcache->connect('localhost', 11211) or die ("Verbindung fehlgeschlagen");

$version = $memcache->getVersion();
echo "Server-Version: " . $version . "<br/>\n";

$objekt = new stdClass;
$objekt->string_attribut = 'test';
$objekt->integer_attribut = 123;

$memcache->set('schlüssel', $objekt, false, 10) or die ("Speichern des Objekts fehlgeschlagen");
echo "Objekt wurde erfolgreich mit einer Lebensdauer von 10 Sekunden gespeichert<br/>\n";

$gespeichertes_objekt = $memcache->get('schlüssel');
echo "Daten wurden aus dem Cache gelesen:<br/>\n";

var_dump($gespeichertes_objekt);

?>

Beispiel #2 Memcache als Session-Handler verwenden

<?php

$session_save_path = "tcp://$host:$port?persistent=1&weight=2&timeout=2&retry_interval=10, ,tcp://$host:$port";
ini_set('session.save_handler', 'memcache');
ini_set('session.save_path', $session_save_path);

?>

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User Contributed Notes 2 notes

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atesin > gmail ¶

4 years ago

memcached is great, is lightning fast, very versatile and useful, scalable, and is a must have for many projects

but if you only want speed to minimize session file blocking there is also a good alternative, tmpfs

https://eddmann.com/posts/storing-php-sessions-file-caches-in-memory-using-tmpfs/

maybe if you are in debian you already had session directory in tmp (mounted as tmpfs), but beware of daily cleaning process that can mess up your sessions

you can use this trick if you are in centos/other (like me) or even if you are in debian but want to get ride of /tmp cleaning task

i realized in my system /run is also mounted as tmpfs, so i shut php-fpm down, moved my php session dir to /tmp/, reconfigure php and start again... (you can adapt it to your situation)

  systemctl stop php-fpm
  cp -a /var/lib/php/session /tmp/php-session
  vim /etc/php-fpm-d/www.conf
  ------
  php_value[session.save_path] = /run/php-session
  ------
  systemctl start php-fpm

the only drawback is tmpfs is VOLATILE, just like memcached (data is lost on unmount/shutdown/power fail), to  circumvent this risk i wrote another service that restores/backup php session dir before/after php starts/stops... (UNTESTED!)

  vim /etc/systemd/system/php-session-backup.service
  ------
  # basic persistence for tmpfs php sessions
  
  [Unit]
  Description=PHP tmpfs sessions backup/restore on shutdown/boot
  Before=php-fpm.service
  
  [Service]
  Type=oneshot
  RemainAfterExit=true
  ExecStart=rm -fr /run/php-session
  ExecStart=cp -fa /var/lib/php/session /run/php-session
  ExecStop=rm -fr /var/lib/php/session
  ExecStop=cp -fa /run/php-session /var/lib/php/session
  
  [Install]
  WantedBy=multi-user.target
  ------
  systemctl enable php-session-backup

you can also complement this with a daily backup task in case of system crash so you will lose just one day

  crontab -e
  ------
  0 4 * * * rm -fr /var/lib/php/session;cp -fa /run/php-session /var/lib/php/session
  ------

this is very rough though, you can better use inotify + rsync, could take some ideas from here

https://blog.jmdawson.co.uk/persistent-ramdisk-on-debain-ubuntu/

down

-1

atesin > gmail ¶

4 years ago

moderator please merge these posts

an errata to my comment done on 2020-07-28 01:05 about tmpfs session dir...

the tmpfs directory i used to install session files is "/run" not "/tmp"...  as /tmp is auto (or manual) deleted sometimes

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