Working with memcache and mysql using memcache_functions_mysql UDFs

Question

I have installed the following packages --

1. libevent-2.0.21
2. memcached-1.4.17
3. libmemcached-0.34
4. memcached_functions_mysql_1.1

All of the above have been installed successfully. The output of the ldconfig -v command (the part where it shows that libmemcached libraries have been included) is as follows:

$ldconfig -v

/usr/local/libmemcached/lib:
        libmemcached.so.3 -> libmemcached.so.3.0.0
        libmemcachedprotocol.so.0 -> libmemcachedprotocol.so.0.0.0
        libmemcachedutil.so.0 -> libmemcachedutil.so.0.0.0

But when I try to load UDF's into mysql using the install_functions.sql that is shipped with memcache_functions it throws the following error:

ERROR 1126 (HY000) at line 38: Can't open shared library 'libmemcached_functions_mysql.so' (errno: 0 libmemcached.so.3: cannot open shared object file: No such file or directory)

And the contents of the plugin directory are:

-rw-r--r-- 1 root root 6.1K Jan 21 13:49 adt_null.so
-rw-r--r-- 1 root root  11K Jan 21 13:49 auth.so
-rw-r--r-- 1 root root 6.0K Jan 21 13:49 auth_socket.so
-rw-r--r-- 1 root root 6.2K Jan 21 13:49 auth_test_plugin.so
-rw-r--r-- 1 root root  35K Jan 21 13:49 ha_example.so
-rw-r--r-- 1 root root  10K Jan 21 13:49 libdaemon_example.so
-rw-r--r-- 1 root root 361K Feb 13 02:47 libmemcached_functions_mysql.a
-rwxr-xr-x 1 root root 1.1K Feb 13 02:47 libmemcached_functions_mysql.la
-rwxr-xr-x 1 root root 167K Feb 13 02:47 libmemcached_functions_mysql.so
-rwxr-xr-x 1 root root 167K Feb 13 02:47 libmemcached_functions_mysql.so.0
-rwxr-xr-x 1 root root 167K Feb 13 02:47 libmemcached_functions_mysql.so.0.0.0
-rw-r--r-- 1 root root  11K Jan 21 13:49 mypluglib.so
-rw-r--r-- 1 root root 5.9K Jan 21 13:49 qa_auth_client.so
-rw-r--r-- 1 root root  11K Jan 21 13:49 qa_auth_interface.so
-rw-r--r-- 1 root root 6.0K Jan 21 13:49 qa_auth_server.so
-rw-r--r-- 1 root root  39K Jan 21 13:49 semisync_master.so
-rw-r--r-- 1 root root  15K Jan 21 13:49 semisync_slave.so

Answer 1

Installing memcached on Ubuntu 12.04.1 LTS (64 bit)

 Python - 2.6.8
 MySQL – 5.5.28
 Zope – 2.12.19

1.  Install memcached

    apt-get install memcached

2.  Install libmemcached -0 .34 (Version is very important. May or may not work with other versions).

    Download it from https://launchpad.net/libmemcached/

    tar xvf libmemcached-0.34.tar.gz
    sudo ./configure  --prefix=/usr/lib/libmemcached  --with-memcached=/usr/bin/memcached
    sudo make
    sudo make install.

3.  Install memcached_functions_mysql (Version 1.1 used at the time of the installation. (To create UDF’s that are invoked by triggers to manipulate the cache).

    Downloading from https://launchpad.net/memcached-udfs

    sudo ./configure  --prefix=/usr/local/memcached_mysql  --libdir=/usr/lib/mysql/plugin  --with-mysql=/usr/bin/mysql_config  --with-libmemcached=/usr/lib/libmemcached
    sudo make
    sudo make install

    Navigate to the “sql” folder inside the memcached_mysql_functions directory.

    mysql –u <username> -p < install_functions.sql

4.  For Zope users

    Install python-memcached-1.53

    Download it from https://pypi.python.org/pypi/python-memcached/
    Navigate to the extracted python-memcached directory.

    /home/zope/zope/bin/python setup.py install

5.  Edit the script containing which imports the modules.

    allow_module('memcache')

    from memcache import Client
    allow_class(Client)
    allow_module('memcache.Client.get')
    allow_module('memcache.Client.set')

This is done so that memcache can be imported and used in your Restricted Python scripts.
If an external method is used to handle the above case, then the file does need to be updated with the above content.