[TYPO3-core] FYI72: bug #9645: Memcached backend is not working properly

[Dmitry Dulepov]

Hi!

Martin Kutschker wrote:
> Hm. So you cannot use the same memcached for more than one installation?
> Or does the prefix alone prevent this?

You can use the same memcached for all installations. Prefix
prevents collisions by using HTTP_HOST.

>> Also I dropped php_sapi_name()
>> in the identifier prefix. php_sapi_name() does not add any value but
>> breaks cache clearing from CLI scripts.
> 
> Good. But I wonder why the prefix uses
> t3lib_div::getIndpEnv('HTTP_HOST'). Won't this clash again with usage
> from CLI scripts? Shouldn't the prefix only denote the TYPO3
> installation and not the domain?  So I would tend to use a hash of
> PATH_site.

PATH_site will have problems if you have, for example, typo3.com and
typo3.org in one installation. I'll check it for CLI again.

>> Also SCRIPT_PATH is dropped
>> because it will not allow to clear cache from BE.
> 
> Why? Same as above?

Because for FE it is /path/to/site/index.php and in BE it is
/path/to/site/typo3/something/else/file.php, thus cache cannot be
cleared because prefix is different for FE and BE. This is not a
problem for FLOW3, where SCRIPT_PATH is always the same.

> As this is a FLOW3 backport I would appreciate if any changes made to
> the caching framework are done in a coordinated manner. It's great that
> you've made this finally run, but please wait with the commit until one
> of the FLOW3 team had the chance to review the patch.

Ok but they have different architecture and therefore some of our
changes (like SCRIPT_PATH) are irrelevant/useless to them. If they
don't review the patch, we will have to drop memcached backend from
4.3 completely. We can't ship a piece of code that does not work at
all...

-- 
Dmitry Dulepov
TYPO3 translations support
My TYPO3 book: http://www.packtpub.com/typo3-extension-development/book
In the blog:
http://typo3bloke.net/post-details/typo3_43_cache_and_memcached_fix_ready/