[TYPO3-dev] cache framework - exception in apc backend when no space is left

[Andreas Kiessling]

Hi,

today i tried to use the cache framework with apc, but was faced with a 
"for me" not understandable exception, that the value could not be set, 
since the opcode cache did work fine and also the server was just idling 
with no signs of errors.

AFAIK apc adresses by default 32MB, and after some reading, i realized 
that this is surely not enough to use it with TYPO3 ;)
We had already upped it to 62MB, but even that was filled up by the 
opcode cache and so there was just no space for any user cache entries. 
When the cache backend tried to write to apc, the apc_store function 
simply returned false. That event may hit you unprepared, probably just 
add an extension that includes a big framework or add some installations 
to your server.

We upped the setting to a limit that we will hopefully never hit, but 
probably the framework should "degrade" in such a case? apc does not 
return a special message if there is not enough space and this is for 
sure some "advanced" option, but the current situation does not really 
make me happy.

Any suggestions on how to proceed? Drop apc and go for memcache? Make 
the apc backend "degradable"?

Regards,
Andreas