Since I've no answer, I still try to find out what happen with my configuration ...
but still didn't have no glue on what hang my postgres
The problem is that I can register a participant to 2 or 3 class an then it's hang the postgres process.
after a few research I find that the posgres process stay waiting like that :
postgres 19720 0.1 0.8 14572 9096 pts/0 S 12:20 0:02 postgres: nsadmin dotlrn_head [local] idle in transaction
postgres 19721 0.0 0.4 10428 5016 pts/0 S 12:20 0:01 postgres: nsadmin dotlrn_head [local] SELECT waiting
and if I try once more time their is a second process waiting and so on till all my process are stuck then I have to restart may OACS system.
it seems to append in the acs_rel__new function
dotlrn_head=# select dotlrn_member_rel__new(NULL,'dotlrn_member_rel',NULL,'21635','27103','needs approval','27103','192.168.1.18');
NOTICE: Adding missing FROM-clause entry for table "acs_object_id_seq"
NOTICE: identifier "acs_object__initialize_attributes" will be truncated to "acs_object__initialize_attribut"
NOTICE: identifier "acs_object_type_get_tree_sortkey" will be truncated to "acs_object_type_get_tree_sortke"
NOTICE: identifier "acs_object_type_get_tree_sortkey" will be truncated to "acs_object_type_get_tree_sortke"
Cancel request sent
NOTICE: Error occurred while executing PL/pgSQL function acs_rel__new
NOTICE: line 22 at SQL statement
If anybody has already experience this kind of problem ... Thank you
Denis