11 Replies Latest reply: Jun 12, 2014 3:23 PM by jgarry RSS

    Issues with 10g client for a 12c server?

    KvonMurphy

      Hi,

       

      I was redirected to this forum, I hope this is the good one.

       

      My customer wants to drop an old 9i server. It's used as a datastore by an old (barely maintened) application which uses a 10g ODBC client, and we don't know much about the internals. We'd like to migrate the data to a new 12c instance and change only the TNSNAMES.ORA on the application.

       

      I was told that a 10.2.0.2 client should be able to connect to a 12c server. But is there known issues?

       

      Basically : is it worth to spend time (and money...) to test?

       

      This seems to be a simple application (a bit of PLSQL, one schema, no fancy feature), but with Paradox and ODBC middleware... and almost no documentation. We'd like to change as few things as possible. A 12c client may work but I don't know how the application would deal with it.

       

      Thank you for any advice

        • 1. Re: Issues with 10g client for a 12c server?
          Maris Elsins

          Hi,

           

          There's a MOS document to address your question: "Client / Server / Interoperability Support Matrix For Different Oracle Versions (Doc ID 207303.1)"

           

          Maris

          • 2. Re: Issues with 10g client for a 12c server?
            sb92075

            >I was told that a 10.2.0.2 client should be able to connect to a 12c server.

            no known issues

            • 3. Re: Issues with 10g client for a 12c server?
              tvCa-Oracle

              The issue is that when you now already use an old (desupported ?) client, things will get worse in the future. That is even assuming you can connect a 10 client to a 12 database. It's not because everybody else ignores all advise and logic, you should do as well.

              • 5. Re: Issues with 10g client for a 12c server?
                KvonMurphy

                In this case (old application near its end of life, no documentation), conservatism is the rule. If the 10g client works, I won't install a 12c client which is unsupported by the application too. We'll see in 2020 if this customer still exists, still needs this old application, and wants to install Oracle 13x.

                • 6. Re: Issues with 10g client for a 12c server?
                  KvonMurphy

                  I do not have to support :-(      (Administrative internal long story, don't ask.)

                  • 7. Re: Issues with 10g client for a 12c server?
                    tvCa-Oracle

                    That's sad, but probably true.

                    • 8. Re: Issues with 10g client for a 12c server?
                      rp0428
                      My customer wants to drop an old 9i server. It's used as a datastore by an old (barely maintened) application which uses a 10g ODBC client, and we don't know much about the internals.

                      The first thing you should do BEFORE anything else is to take a full backup of that database. You should also make sure you have complete documentation that includes the directory structure, all file names and locations, copies of the initialization files being used.

                       

                      Also - if the version of that database is older than 9.2.0.4 you might consider upgrading to that patch version if possible.

                      We'd like to migrate the data to a new 12c instance and change only the TNSNAMES.ORA on the application.

                      Why 12c? Why not 11g? There are several things you should consider before choosing the version:

                       

                      1. You can 'upgrade' directly to 11g from 9.2.0.4 See this white paper - http://www.oracle.com/technetwork/database/manageability/9i-to-11g-real-world-customer-exper-133754.pdf

                       

                      2. you can NOT upgrade directly to 12c - you need to use an 'other' method. See this white paper

                      http://www.oracle.com/technetwork/database/upgrade/upgrading-oracle-database-wp-12c-1896123.pdf

                       

                      You could use either transportable tablespaces (recommended) or the original export/import utilities. You can't use data pump (expdp/impdp) since that wasn't introduced until 10g.

                       

                      Do you have ANY experience with 12c installation and configuration? If not and you decide to go with 12c you may want to create a traditional instance and NOT use the new multi-tenant architecture.

                      I was told that a 10.2.0.2 client should be able to connect to a 12c server. But is there known issues?

                      The client is the LEAST of your possible problems but yes, you can use a 10g client.

                      Basically : is it worth to spend time (and money...) to test?

                      That is your decision to make. And it mostly depends on how you plan to resolve any issues that arise. Will the old system still be up and running if you need to query/examine it to help troubleshoot a problem?

                       

                      Your 9i backup files will be useless in a 12c environment so if the 'upgrade' is not problem free you will need to either 'fix' the issues and redo the upgrade or you will need to find and fix any problems manually.

                       

                      If you don't perform adequate testing you may find that you have missing data or system objects. It all depends on what features/functionality your old system uses: grants, LOBs, users, etc.

                       

                      It is easy to move data. It can be much harder to find and regenerate missing grants and objects if you have to do it manually.

                      • 9. Re: Issues with 10g client for a 12c server?
                        KvonMurphy

                        Well, upgrading the 9i database is out of question, it would be a new instance and I hope that exp/imp work as expected.

                         

                        No multitenant or fancy feature, the target is only a Standard Edition One.

                         

                        As I have no documentation, no access to the application (yet), as the customer does not know much more and the original application provider is not cooperative (it would prefer to sell the expensive latest version), we hope that the database structure is as simple as it seems. I agree, this is risky.

                        • 10. Re: Issues with 10g client for a 12c server?
                          Brian Bontrager

                          Basically : is it worth to spend time (and money...) to test?

                           

                          As I have no documentation, no access to the application (yet), as the customer does not know much more and the original application provider is not cooperative (it would prefer to sell the expensive latest version), we hope that the database structure is as simple as it seems. I agree, this is risky.

                           

                          Testing seems imperative, then.  If the vendor is not giving you support and you are out of Oracle support, testing on your own is the only way to verify everything works in your new combination of software versions.  "A forum on the Internet said it was probably OK" does not mitigate the level of risk you describe.

                          • 11. Re: Issues with 10g client for a 12c server?
                            jgarry

                            "No known issue" implies "yet."