[TYPO3-core] RFC #0011317: Backport treelist caching from TYPO3 4.3 to TYPO3 4.2.6

[Rupert Germann]

Hi,

this is a SVN patch request.

Type: performance improvement

Bugtracker references:
http://bugs.typo3.org/view.php?id=11317

Branches: 
4_2 only

Problem:
function getTreeList() in class tslib_content can be some of the most
expensive functions when rendering pages showing plugins that use huge
pidlists.

Solution:
Backport the treelist caching from TYPO3 4.3 to TYPO3 4.2.6
(There are no DB changes needed because I use cache_hash for storing cached
treelists instead of an extra table like it is done in 4.3) 

my performance benchmarks showed that at least in my testing environment
caching the treelist resulted in rendering uncached pages up to 2 (!) as
fast as before. Same goes for pages with user_int objects using a pidList.


greets
rupert