Is APC compatible with PHP 5.4 or PHP 5.5?
As of PHP 5.4.7 and APC 3.1.13 (and even APC SVN trunk as of 2012-09-19), although it is "compatible" it is not stable on servers with heavy load, particularly if you're using PHP-FPM and $GLOBALS. Some of the developer discussions on APC talk about unresolved fringe cases.
I'm answering this question 6 months after it was asked because the problem is still prevalent, and encountering this thread w/o an answer like mine is what made me make the leap to PHP 5.4 w/ APC and get burnt. Hopefully this will help people avoid some pain.
Zend OPCache included in PHP 5.5
On the 21st March 2013, the PHP 5.5 beta 1 was released including "Zend OPCache" - It looks firmly like this will be the replacement for APC going forward as it is included in the PHP core, and will have to be maintained for each new release.
I would personally advise those who depend on APC for it's opcode caching to test their code with the upcoming built-in opcode cache, and feed back any issues encountered to ensure a stable final release.
I do not know what this means for the future of APC.
APC FOR PHP 5.4+ IS STILL FLAGGED AS BETA
This means the developers do not consider it completely stable. While many people are experiencing no problems at all with the current SVN releases, there is still the odd report of edge cases from people under certain configurations, or under heavy load.
As with everything you would want to use in a production environment, make sure you thoroughly test any release (beta or stable) in development or pre-production environments first. This includes load testing!
As of the 3.1.13 release, commits to the SVN repository have slowed down somewhat and the bug list doesn't have that many recent additions. Make of that what you will.
On 10 December 2012 21:05, Rasmus Lerdorf wrote:
APC is at the point now for 5.4 where I don't think there are any more edge cases than we have in 5.3. Neither is perfect, but it is close enough for the majority of sites.
Anyone with C / gdb skills and some free time is urged to gloss over the bug list and see if they can fix anything, or improve this free open source product that we all rely on.
Alternative solutions exist, Wikipedia provides a list of PHP accelerators.
On the 13th of February 2013, Zeev Suraski announced the availability of the Zend Optimizer+ source code.
There has been quite a lengthy discussion about integrating Zend Optimizer+ into the PHP core in the next major version (the version after 5.5). People may wish to familiarise themselves with Zend Optimizer+ in advance, should this be the case.
Do not use APC 3.1.14
APC 3.1.14 has been removed from PECL downloads due to some serious memory issues that have been discovered but have not yet been tracked down.
If you're already using 3.1.14, you may wish to downgrade until 3.1.15 is released. Remember, this is still beta. If you are using it at all, you are using it at your own risk.
2013-01-02:APC 3.1.14 is available, adding PHP 5.5 compatibility, in addition to resolving a fair number of other bugs.
Still beta
2012-09-03:
APC 3.1.13 is available, fixing a number of segfaults.
2012-08-16:
An APC 3.1.12 tag has been created, but is still marked as beta, its available on the APC PECL page, as well as the changelog.
Lots of bin_dump related bugs fixed this time around.
2012-07-19:
An APC 3.1.11 tag has been created, but is still marked as beta, its available on the APC PECL page, as well as the changelog. I've been following the relevant mailing lists, and they are still actively working on fixing APC bugs however it is a complex module and not many people seem to be up to the task. This release fixes the nasty stat=0 bugs when including files.
2012-04-11:
An APC 3.1.10 tag was created today, and a beta release of 3.1.10 was placed on the APC PECL page
The changelog states:
- Add PHP 5.4 support (Dmitry, Anatoliy, Pierre)
- Fixed bug #22679: Fix apc_bin_dump for constants. Use IS_CONSTANT_TYPE_MASK to handle all the constants, including the unqalified ones (instead of ~IS_CONSTANT_INDEX check)
- Fixed bug #23822, php crashes on apache restart