The TYPO3 caching framework in TYPO3 4.5.0 runs into troubles when using memcached backend on Debian Squeeze. It seems that Squeeze ships a broken php5-memcache package, which does not fit the API of memcached 1.4.4. Since Squeeze is already released, there will be no fix in the official stable repository. But I provide a fixed package for download.
The php5-memcache package implements parts of outdated memcached API. Deleting entries with expiration time does not work properly. The memcache backend of the TYPO3 caching framework in 4.5.0 does so and runs into troubles. It throws an error:
CLIENT_ERROR bad command line format. Usage: delete <key> [noreply]
Unfortunately Squeeze was released before I realized this issue. That means there will be no fixed package in the stable repository because of release policy. At the time of writing this article, I also could not find a fixed package somewhere else. The original patch from upstream is a two-liner, so I took the chance to fix it and build a new package myself.
You can download the fixed php5-memcache package and use it as-is. ATM there's only a built for amd64. If you need other ports, please leave a comment. I am sorry that there's no "real" package repository, but I did not have the time to set it up properly. Maybe I find some later.
This is how to install the package:
$ cd /tmp/
$ wget http://www.t3node.com/debian/php5-memcache_3.0.4-4+t3node-1_amd64.deb
$ sudo dpkg --install /tmp/php5-memcache_3.0.4-4+t3node-1_amd64.deb
Use at your own risk since this package comes with NO WARRANTY and is provided AS-IS. There's also a tarball with the source code available for download.