[TYPO3-dev] Caching Framework

[Nikolas Hagelstein]

Hi,
> I didn't know that there is such a restriction with xcache. AFAIK there
> is no such restriction when
> you use memache.

It's not just xcache is related to all shm based caches (apc, eaccelerator
etc.).
It's a general problem within a fast-cgi environment.

Another aspect is, that not only custom data is effected  but cached opcode
(for performance optimization) as well.

BTW: eAccelerator is the only (known to me ) opcode cache capable of
optionally storing it's cache data (customdate/opcode) to disk.

So it's not that easy to well balance such an environment in regard to
memory consumption, effective shm(cach/opcodecache) 
usage and performance etc. But this is really another story ;).

Memcache uses a separated daemon and clients communicate to it via sockets
or tcp/ip.

So data stored by memcached deamon is available  across all php instances
(referring to the fast-cgi sample) 
- even if they reside on different machine.

But using memcached in a single machine scenario does not make much sense, 
since client/server communication is quite costy.

It's actually intended to be used in multi machine environment, as already
stated by someone else in this thread ;>.

Regards,
Nikolas