Re: apc and ZendPlatform

Quoting Jochem Maas <jochem@iamjochem.com>:

Rick Emery wrote:

We're running Zend Platform on a server that also has apc installed; we're using apc in the scripts to cache data, and I understand (I think) that it also does bytecode

also often referred to as 'opcode' caching

That's what I meant; sorry.

caching.

correct.

Zend Platform includes a php accelerator, which (I think) is also caching bytecode.

AFAIK also correct.

Does anybody know if we'll see adverse effects from this?

only if you turn on both accelerators (opcode caches) - at least trying to run both is more than likely to open up a whole can of worms and leave your webpages fairly blank. I can't see how they could work together and given that they do the same job (as far as opcode caching is concerned) there is nothing to be gained from running both (for opcode caching)

Okay. We haven't seen any problems so far. I just "discovered" the documentation (which was in such an obvious location that I'm embarassed I didn't find it last time I looked: http://www.php.net/apc), and it looks like we have apc.optimization turned off. In the documentation, it looks like optimization is experimental, so I guess we'd be better off sticking with Zend Optimizer and using apc for data caching (I guess what I really want is to know if people agree or disagree)?

apc comes with a cool page (apc.php) that shows information about its cache. While it shows that scripts are being cached, it's showing 0 hits for all of them. That seems wrong to me, but I may be mis-understanding it. Does anybody have any insight?

check what phpinfo() is saying about your apc settings. my guess is apc.cache_by_default is set to false and apc.filters is empty .... which affectively means no files will be cached ... it could be then the zend platform is forcefully setting this at start up to avoid a conflict/crash/segfault/whatever.

apc.cache_by_default is on, but apc.filters says "no value". Let me see if I'm understanding the documentation correctly...it looks like apc does (basically) three things: 1. Cache data (such as information retrieved from a database) 2. Optimize opcode 3. Cache opcode I need to be able to cache data. If I set apc.cache_by_default to off, can I still cache data within the application using apc_store and apc_fetch? Thanks, Rick