Kevin Kempf's Blog

October 17, 2014

Querying your 11i/R12 Context File from Oracle SQL*Plus

Filed under: 11i, R12.2 — kkempf @ 8:53 am



Peeling back the layers of the context file, precipitated by MSCA

We all know that the context file holds information about virtually everything on the applications tier, and how important it is.  As a result of our upgrade effort from 11i to R12.2, I started getting incessant calls wanting to know that current dispatcher port for MSCA. While this post will be specific to MSCA as the reason for having to figure out how to do this query, the principles here can be used to obtain any value from the context file via SQL*Plus, for any reason.


I should note a few things about the MSCA product for those (presumably the majority of you) who are unfamiliar with it.  The MSCA product is essentially a telnet front end, which runs on the application server on a specific port.  Users can either use telnet to connect to it, or the MSCA GUI client.  Either one requires a hostname and port.  MSCA actually runs on many ports, managed by a dispatcher to reduce the load on any one port.  So ideally, users connect to the dispatcher.  Thus one would think that when I created a new environment, it would be easy to just inform everyone of the port to connect to and the calls would end.  In my case, there’s two problems with that.  First, there’s a known R12.2 bug which switches the dispatcher port during an online patch session.  So if you’re running on filesystem1, it might be 10300, but if you’re on filesystem2, 10302.  Second, MSCA doesn’t like to stay running.  So it’s helpful for a user to confirm they’re trying to connect to the correct port before calling.

The good part

The bottom line is the query to accomplish this is as follows; the table fnd_oam_context_values stores entire context files as clobs in a field called text.

extractvalue( xmltype( text ),’//mwaDispatcherPort‘ )
status = ‘S’
and name = ‘SID_hostname
and last_synchronized =
max( last_synchronized )
status = ‘S’
and name = ‘SID_hostname
) ;

Obviously, when you do it, you’re going to change a few things:

  • mwaDispatcherPort is the tag from the $CONTEXT_FILE you’re looking for the value of.  Examples include oa_context_name, jinit_ver_dot, platform, or whatever you’re looking for.
  • SID_hostname is the database SID followed by an underscore and the applications tier hostname.

Why the subquery?  There are many context files stored in this field as clobs.  You want the most recent one (presumably, tweak as desired, based on last_synched) and you want one which has a value of S (synched? not 100% sure about this column, just figured it out through trial and error)

Incidentally, there is a table called fnd_env_context which holds some, but not all of the values contained in the context file.

End Result

We’re gunning for a centralized APEX report which can query the databases and return the relevant port numbers for users, as appropriate, depending on their apps responsibility.  So they can stop calling me so I can blog more.


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