Attaching to a session using APEX_PLSQL_JOB

Question

Hi All,
I'm going bonkers as I can't see why something isn't working! Basically, I have a process that is started by the user from a page within my application. This process can take a while (a number of minutes) and causes the browser to timeout thinking that the session has died (at least I think that is what is happening). So to work around this I want to submit a job via APEX_PLSQL_JOB and then have the page check every X seconds to see if that job has completed.
The process makes use of collections to temporarily store the output during computation. So to enable this I need to attach to a session and thought I might as well use the submitting users session. Trouble is I get an error at the session attach stage and can't quite work out why exactly. So first up my 'session attach' procedure (which is in a package) is as below:
PROCEDURE sessionattach(
   p_user       VARCHAR2
, p_session    VARCHAR2
, p_app_id     VARCHAR2
, p_page_id    VARCHAR2)
IS
BEGIN
   -- Session attach.
   APEX_CUSTOM_AUTH.define_user_session(p_user, p_session);
   APEX_APPLICATION.g_flow_id := p_app_id;
   APEX_CUSTOM_AUTH.post_login(p_user, p_session, p_app_id || ':' || p_page_id);
END sessionattach;When I create the job I know that the following is being passed in (it's not doing the actual work as I can't get past this stage):
BEGIN
   master_data_pkg.sessionattach(p_user => 'MYUSERNAME', p_session => '4260523061121888', p_app_id => '101', p_page_id => '527');
END;Again I know that each of the parameters is correct as I'm logging the job SQL that is produced. The error stack that is produced is:
ORA-06512: at "SYS.OWA_UTIL", line 354
ORA-06512: at "SYS.HTP", line 1368
ORA-06512: at "SYS.HTP", line 1443
ORA-06512: at "SYS.HTP", line 1735
ORA-06512: at "FLOWS_030100.WWV_FLOW_CUSTOM_AUTH_STD", line 1075
ORA-06512: at "FLOWS_030100.WWV_FLOW_CUSTOM_AUTH_STD", line 662
ORA-06512: at "FLOWS_030100.HTMLDB_CUSTOM_AUTH", line 238
ORA-06512: at "APEXUSR.MASTER_DATA_PKG", line 2114
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at "SYS.OWA_UTIL", line 354
ORA-06512: at "SYS.HTP", line 1368
ORA-06512: at "SYS.HTP", line 1443
ORA-06512: at "SYS.HTP", line 1735
ORA-06512: at "FLOWS_030100.WWV_FLOW_CUSTOM_AUTH_STD", line 1075
ORA-06502: PL/SQL: numeric or value errorNow the bit where I get really stuck is if I try and run the session attach from a SQL Developer session, the first time it runs it comes up with the same error stack, but if I run it again I get no error. However, I am still not attached to the session as, if I try and create a collection, I get an ORA-20104/ORA-20001 Invalid parsing schema error.
Any suggestions as to where I'm going wrong and what mistake I am making?
Many thanks,
Gareth.

Answer 1

Ok, I finally resolved the issue by basically using Scotts method in the last post of Re: How to create an Apex 3.1 a session context programmatically? thread.
The only real change I made was to not bother with the setting of a page variable (I assumed this was just to test) and instead of setting apex_application.g_instance to the next session ID I used the one provided by the users session that launched the job.
This allows me to create and, if required, query collections from that users session.
I hope that helps someone else.
Regards,
Gareth.