[TYPO3-v4] Core performance for 4.6 and beyond

[Dmitry Dulepov]

Hi!

François Suter wrote:
> This discussion is getting pretty troubling. What's the issue exactly?
> Why is it not recommended to use memcached and how come it is used
> (apparently successfully) by high traffic sites?

It is due to tags. Memcache can throw away elements if it runs out of 
memory. So it can throw away a block with tag information. So you will not 
be able to clear cache by tags and will get wrong entries. Same for APC.

Also tag handling for memcache is very inefficient. Sometimes it takes 
minutes to clear cache using tags, which is not acceptable in FE.

-- 
Dmitry Dulepov
TYPO3 core&security team member
E-mail: dmitry.dulepov at typo3.org
Web: http://dmitry-dulepov.com/