I vacuumed and analyzed postgres and installed developer support.
The Developer Support says the following:
5 database commands totalling -1877234293 ms
Page served in 402999323 ms
01:05:20 134.155.53.42 GET /ds/
01:05:18 321650 ms 134.155.53.42 GET /dotlrn/user-add-3
01:05:15 324516 ms 134.155.53.42 GET /ds/request-info?request=214
01:03:57 402999 ms 134.155.53.42 GET /dotlrn/user-add-3
01:03:15 444857 ms 134.155.53.42 GET /dotlrn/design/images/zufall/015.jpg
01:03:15 444902 ms 134.155.53.42 GET /dotlrn/design/images/spacer.gif
01:03:15 444906 ms 134.155.53.42 GET /dotlrn/design/images/zufall/logoUniMannheim.gif
01:03:15 444960 ms 134.155.53.42 GET /dotlrn/design/scripts/zufallscript.js
01:03:15 445039 ms 134.155.53.42 GET /dotlrn/stylesheets/portlets.css
01:03:15 445085 ms 134.155.53.42 GET /dotlrn/design/stylesheets/uni-headerFooter.css
01:03:15 445189 ms 134.155.53.42 GET /dotlrn/dotlrn-master.css
01:03:14 445465 ms 134.155.53.42 GET /dotlrn/user-add-2?read%5fprivate%5fdata%5fp=t&can%5fbrowse%5fp=1&...
01:03:10 449318 ms 134.155.53.42 POST /dotlrn/admin/user-new-2
01:03:04 455951 ms 134.155.53.42 GET /dotlrn/admin/design/images/spacer.gif
01:03:04 455967 ms 134.155.53.42 GET /dotlrn/design/images/zufall/006.jpg
01:03:04 455983 ms 134.155.53.42 GET /dotlrn/design/images/zufall/logoUniMannheim.gif
01:03:04 456026 ms 134.155.53.42 GET /dotlrn/design/scripts/zufallscript.js
01:03:04 456089 ms 134.155.53.42 GET /dotlrn/admin/stylesheets/portlets.css
01:03:04 456133 ms 134.155.53.42 GET /dotlrn/design/stylesheets/uni-headerFooter.css
01:03:03 456220 ms 134.155.53.42 GET /dotlrn/dotlrn-master.css
01:03:03 456399 ms 134.155.53.42 GET /dotlrn/admin/user-new-2?referer=%2e%2e%2fuser%2dadd%2d2%3fread%255fpriv...
01:03:03 456556 ms 134.155.53.42 GET /dotlrn/user-add-2?read%5fprivate%5fdata%5fp=t&can%5fbrowse%5fp=1&...
01:03:02 457658 ms 134.155.53.42 POST /dotlrn/user-add
01:02:44 475609 ms 134.155.53.42 GET /dotlrn/design/images/zufall/008.jpg
01:02:44 475873 ms 134.155.53.42 GET /dotlrn/user-add?add_membership_p=f&dotlrn_interactive_p=1&refer...
01:01:49 530318 ms 134.155.53.42 GET /dotlrn/design/images/zufall/019.jpg
