7 Replies Latest reply: Jan 24, 2013 9:15 AM by mmaller0319 RSS

    _ignore_Desc_in_index

    mmaller0319
      Current Version 84819
      App 8.9
      Database 10.2.0.4.0

      We are Upgrading to

      85212
      App 91.fp2
      Database 11.2.0.3.0

      Can you tell me what should be the recommended setting for ignoredesc_in_index when we upgrade to 11g R2 ?
        • 1. Re: _ignore_Desc_in_index
          HakanBiroglu
          Hi,

          See following docs saying all the same: set this property to TRUE if you experience performance issues (which is a subjective opinion to start with)
          E-ORA PeopleSoft Functional or DESC indexes cause performance issues. [ID 1302068.1]
          E-ORA: Descending Index Performance Issues in Oracle Databases [ID 662220.1]
          E-ORA: CLSAUDIT.SQR: Unable to Extend Temp Segment PSTEMP [ID 1197064.1]

          Also see this blog from Nicolas saying the parameter is by default false.

          I also fired up my OVM template sandbox (PeopleSoft installation delivered by Oracle) and this parameter is not defined in the init.ora, so parameter should be false and only be set to true if you experiencing issues.

          Regards,

          Hakan

          Edited by: Hakan Biroglu on Jan 24, 2013 9:25 AM
          • 2. Re: _ignore_Desc_in_index
            Nicolas.Gasparotto
            Yes, it's still recommanded to set it to true. And keep in mind that if you are changing the value of that parameter you will have to rebuild all and every indexes.

            Nicolas.
            • 3. Re: _ignore_Desc_in_index
              HakanBiroglu
              Nicolas,

              Now I am confused.
              Should this parameter be false or true by default?

              Regards,

              Hakan
              • 4. Re: _ignore_Desc_in_index
                Nicolas.Gasparotto
                Hakan, the default value is "false" and cause a lot of performance troubles. In previous release it even raises some ORA-600 errors.
                By setting this parameter to "true", you workaround an Oracle bug which is misled and have a wrong explain plan. It seems this bug will be solve in future 12c... to be followed.
                If this parameter is not set to true in Peoplesoft OVM (I don't have one to verify), it does not surprise me. PSOVM is nothing but the bare minimum configuration for a demo, most likely we don't care about bad performance on a demo, right ?

                Nicolas.
                • 5. Re: _ignore_Desc_in_index
                  HakanBiroglu
                  Ok just checking

                  So, it is wise for mmaller0319 to set this parameter straight to TRUE during this upgrade?

                  Hakan
                  • 6. Re: _ignore_Desc_in_index
                    Nicolas.Gasparotto
                    Of course it has to be discussed and tested, but I think it's a recurrent issue for the last few years and Oracle versions.
                    Find out more +Required Interim Patches for the Oracle Database with PeopleSoft [ID 1100831.1]+*
                    tab "Oracle 11gR2 - 11.2.0.3.0" - bug number 11072246

                    Nicolas.
                    • 7. Re: _ignore_Desc_in_index
                      mmaller0319
                      Just to let you know when i was on 8.48 this parameter was FALSE all the time in its run time of 3 years and we never encountered performance issues.

                      Here now in 11gR2 and 8.52 Tools ,its again set to FALSE and i would not want to set it to TRUE unless an issue shows up on same lines.

                      I am just trying to be proactive here.

                      Should i wait to see if performance issues will come and then if i determine they are because of this init ora parameter,set it to TRUE.
                      Or

                      Are there some generic Navigations or SQL that i can execute on the Upgraded PeopleSoft that can right away tell me that performance is not as expected and then make the init ora parameter to TRUE?

                      Finally Also after i GO LIVE and i find performance issues due to the same what should be my approach then?