If you want to test the gb.memcached component - which provides you with a Memcached client - then you need the Memcached server (MCS) on your system.
You can find a detailed description of the Memcached server protocol on the following websites
https://github.com/memcached/memcached/blob/master/doc/protocol.txt
The Memcached server can be installed via the application management or you can enter the following lines in a terminal:
$ sudo apt-get update $ sudo apt-get upgrade $ sudo apt-get install memcached
This is how you determine the status of the Memcached server, as the Memcached server is started immediately after installation and listens on the (standard) port 11211:
$ service memcached status or $ /etc/init.d/memcached status
Output in a console:
hans@mint20:~$ service memcached status
● memcached.service - memcached daemon
Loaded: loaded (/lib/systemd/system/memcached.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2021-03-23 11:53:29 CET; 33min ago
Docs: man:memcached(1)
Main PID: 4900 (memcached)
Tasks: 10 (limit: 18941)
Memory: 2.0M
CGroup: /system.slice/memcached.service
└─4900 /usr/bin/memcached -m 64 -p 11211 -u memcache -l 127.0.0.1 -P /var/run/memcached/memcached.pid
Mär 23 11:53:29 mint20 systemd[1]: Started memcached daemon.
Generally applies to the controller:
$ /etc/init.d/memcached {start|stop|restart|force-reload|status}
or
$ service memcached {start|stop|restart|force-reload|status}
If you are constantly working with the Memcached server, it is worth creating starters on the desktop for selected actions such as starting or stopping; the default configuration does not normally need to be changed. The configuration file can be found here:
/etc/memcached.conf
and log files there:
/var/log/memcached.log
For an initial test, which should also show you the basic operation of the MC-Server and MC-Client, you can use the telnet programme as a Memcached client - with the IP address 127.0.0.1 and port 11211.
The following concept should be implemented:
Console:
# telnet hostname/ip port hans@mint20:~$ telnet 127.0.0.1 11211 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. # version version VERSION 1.5.22 # set key_name meta_data expiry_time_in_seconds length_in_bytes set TESTKEY 0 100 8 # + ENTER MINISINI STORED # get key_name get TESTKEY VALUE TESTKEY 0 8 MINISINI END # replace key_name meta_data expiry_time_in_seconds length_in_bytes replace TESTKEY 0 100 9 GIANLUIGI STORED # delete key_name delete TESTKEY DELETED # stats stats STAT pid 4900 STAT uptime 9032 STAT time 1616505839 STAT version 1.5.22 ... STAT direct_reclaims 0 STAT lru_bumps_dropped 0 END # flush_all flush_all OK # quit quit Connection closed by foreign host. hans@mint20:~$
Overview of selected messages of the MC server:
The Memcached server only shows its strengths when you save the data to be saved in a modified form.
# telnet hostname/ip port hans@mint20:~$ telnet 127.0.0.1 11211 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. # set key_name meta_data expiry_time_in_seconds length_in_bytes set TestKey 0 100 6 # ENTER Gambas STORED # get key_name get TestKey VALUE TestKey 0 6 Gambas END # replace key_name meta_data expiry_time_in_seconds length_in_bytes replace TestKey 0 100 13 Gambas 3.15.2 STORED # delete key_name delete TestKey DELETED # stats stats STAT pid 4900 STAT uptime 9032 STAT time 1616505839 STAT version 1.5.22 ... STAT direct_reclaims 0 STAT lru_bumps_dropped 0 END # flush_all flush_all OK # quit quit Connection closed by foreign host. hans@mint20:~$
Whether Memcached is the best option as a caching solution depends on the requirements and complexity of the respective application. The temporary storage system is particularly useful for web applications with high traffic and pages that access huge databases, for example.