MEMCACHED

Andrei Dragus

OpenSIPS

Edited by

Andrei Dragus

Edited by

Vladut-Stefan Paiu

Revision History
Revision $Revision: 5901 $$Date$

Table of Contents

1. Admin Guide
1.1. Overview
1.2. Advantages
1.3. Limitations
1.4. Dependencies
1.4.1. OpenSIPS Modules
1.4.2. External Libraries or Applications
1.5. Exported Parameters
1.5.1. cachedb_url (string)
1.5.2. exec_threshold (int)
1.5.3. Exported Functions

List of Examples

1.1. Set cachedb_url parameter
1.2. Use memcached servers
1.3. Set exec_threshold parameter

Chapter 1. Admin Guide

1.1. Overview

This module is an implementation of a cache system designed to work with a memcached server. It uses libmemcached client library to connect to several memcached servers that store data. It uses the Key-Value interface exported from the core.

1.2. Advantages

  • memory costs are no longer on the server

  • many servers may be used so the memory is virtually unlimited

  • the cache is persistent so a restart of the server will not affect the cache

  • memcached is an open-source project so it can be used to exchange data with various other applicationsr

  • servers may be grouped together (e.g. for security purposes : some can be inside a private network, some can be in a public one)

1.3. Limitations

  • keys (in key:value pairs) may not contain spaces or control characters

1.4. Dependencies

1.4.1. OpenSIPS Modules

None.

1.4.2. External Libraries or Applications

The following libraries or applications must be installed before running OpenSIPS with this module loaded:

  • libmemcached:

    libmemcached can be downloaded from: http://tangent.org/552/libmemcached.html. Download the archive, extract sources, run ./configure, make,sudo make install.


    ...
    wget http://download.tangent.org/libmemcached-0.31.tar.gz 
    tar -xzvf libmemcached-0.31.tar.gz
    cd libmemcached-0.31
    ./configure
    make
    sudo make install
    ...

1.5. Exported Parameters

1.5.1. cachedb_url (string)

The urls of the server groups that OpenSIPS will connect to in order to use the from script cache_store,cache_fetch, etc operations. It can be set more than one time. The prefix part of the URL will be the identifier that will be used from the script.

Example 1.1. Set cachedb_url parameter

...
modparam("cachedb_memcached", "cachedb_url","memcached:group1://localhost:9999,127.0.0.1/");
modparam("cachedb_memcached", "cachedb_url","memcached:y://random_url:8888/");
...
	

Example 1.2. Use memcached servers

...
cache_store("memcached:group1","key","$ru value");
cache_fetch("memcached:y","key",$avp(10));
cache_remove("memcached:group1","key");
...
	

1.5.2. exec_threshold (int)

The maximum number of microseconds that a local cache query can last. Anything above the threshold will trigger a warning message to the log

Default value is “0 ( unlimited - no warnings )”.

Example 1.3. Set exec_threshold parameter

...
modparam("cachedb_memcached", "exec_threshold", 100000)
...
	

1.5.3. Exported Functions

The module does not export functions to be used in configuration script.