[TYPO3-dev] Very bad BE performance when loading the form for creating/editing a CE

[Uschi Renziehausen]

Dear devs,

in our university project we encountered a performance problem that 
makes certain parts of the BE very frustrating to use for ordinary 
authors when working with CE forms like text or text with image.

Situation:
- Pagetree currently has 2500 pages and will at least double up in the 
following 3 months.
- ALL editors need to be able to link to ALL pages of the tree (e.g. 
using CType menu) regardless whether they are allowed to edit a page or 
not. That means, they need at read access to the whole pagetree.
- We are using be_acl, typo3 4.2 dev (latest branch).
- Each editors' group has at least 2 dbmounts
	a) one for the part of the pagetree they are responsible for
	b) one for the whole pagetree with read only to be able to link to all 
pages


Some statistics:
I made some tests by  simply counting how long it takes to load something.

As an admin

Loading the pagetree (Web->Page): 3
Loading pagecontent (clicking on the title of a page): 2
Loading CE Text form (clicking on the icon in new content element wizard): 3
Saving the CE Text: 3

As an editor with only one DB-mount a (some 80 pages)

Loading the pagetree (Web->Page): 3
Loading pagecontent (clicking on the title of a page): 3
Loading CE Text form (clicking on the icon in new content element 
wizard): 5 (!!!)
Saving the CE Text: 5


As an editor with 2 DB-mounts (a and b)

Loading the pagetree (Web->Page): 5
Loading pagecontent (clicking on the title of a page): 4
Loading CE Text form (clicking on the icon in new content element 
wizard): 18 (!!!)
Saving the CE Text: 6

As you can see, the size of the pagetree has an enormous impact on how 
long it takes to load the editing form for a CE. Counting to 18 until a 
form shows up will put editors into a very bad mood.

Any ideas what might be the bottleneck and how performance could be 
improved?

Regards, Uschi