Avoid Poor Performance and Wrong Results in

One of the best notes in MOS got refreshed last night for Oracle Database It has not only information about performance bugs but also about the worst and meanest category of issues, wrong query result bugs. Those are the ones I call the “sleeping beauties” as you as a DBA usually won’t recognize them. It is recognized at the application level when the result of a report is incorrect or instead of 4 rows just 3 rows get delivered in the output. Therefore you should be highly aware of those and add this note to your bookmarks.

MOS Note 1645862.1Things to Consider Before Upgrading to to Avoid Poor Performance or Wrong Results

And in case you don’t want to move to Oracle but searching for information and known issues in Oracle or Oracle then please find the corresponding documents:

  • MOS Note: 1320966.1 Things to Consider Before Upgrading to to Avoid Poor Performance or Wrong Results
  • MOS Note: 1392633.1 Things to Consider Before Upgrading to to Avoid Poor Performance or Wrong Results


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18 thoughts on “Avoid Poor Performance and Wrong Results in

  1. Oracle RAC Installation on OL7/RHEL 7.

    Can you please tell me did u faced any issues or any changes after or during the installation. Did you people find any performance issues/bugs.

    We have an new build project, So just want to know can i recommended the on RHEL 7(because in future i may need to upgrade db to 12C).



  2. Preethi,

    right now all the customers we are working with are going to – is really LONG TIME AGO for us 😉

    You may check the slides for 11g (scroll down in the Slide Download Center to your right until the bottom – there’s the unchanged 11g deck with issues highlighted).


  3. Hello Mike,
    Good day.

    We are moving to a virtual platform from to since the support for has ended.
    Will you be kind enough to let us know what changes this release brings to the table.
    We are supposed to be on N-1 patch level framework and hence the lower version.


  4. Manish,

    sorry but I’ll be unable to provide you all the changes involved with You may please check the Upgrade Companion on MOS (see Behaviour Changes section) and the Upgrade Guide as it contains a good number of changes to views etc.


  5. Hi Mike,

    Hope you are doing good.

    I am really facing some serious performance issues on Oracle with OS as Solaris SPARC 10. Export of 60GB full dump takes 1.5 day for example.

    I have not installed any patches of Solaris and Oracle from the beginning.

    Do you suggest installing all latest patches for Solaris and Oracle? Please suggest.


  6. Jauhari,

    without knowing more details I can’t give you a good advice.

    My first assumption would always be:
    You have LONG/LOB data in your tablespace(s) somewhere. That will slow down Data Pump. Furthermore make sure you always set EXCLUDE=STATISTICS as the export of stats will slow down the entire action.

    Furthermore alter the PARALLEL parameter to have more workers do the job and use in addition a set of dumpfiles instead of only one single dump file.


  7. Hi Mike,
    I would need the following information as we are planning for Oracle Database Upgrade from to in our Exadata Environment.

    1.Any known issues if you or your team faced while doing this upgrade.
    2.Any do’s and don’t that we have to follow for the upgrade.

    It would be a great help if you can tell us this information.

    Thanks in Advance


  8. Hi All, I need help from you.

    I am using Oracle database server and recently i am facing some slowness in my application. If i restart the database then my application is working fine for 4/5/6hours then again getting slow.

    (FYI, I am for server and for client and connecting the server through ODBC)

    So can you please advice


  9. May I kindly ask you to:
    (1) Upgrade to Oracle Database or as soon as possible?
    (2) The apply the most recent Bundle Patch on top

    Both installations can happen without interrupting your business as you’ll install it into a new Oracle Home anyways.

    Then you run the preupgrade check (either utlu112i.sql for 11.2 or preupgrd.sql for 12.1 upgrades – in any case take the most recent version of the script from MOS 884522.1).

    Then you upgrade.

    Check our big slide deck for gotchas and tips and tricks (Slides Download Center – Upgrade/migrate/consolidate to 12c).


  10. Hi Mike,

    Thank you so much for your response and valuable suggestions/advice. Yes i can do that and FYI, I am very new to this upgrade process. So can i do EXPDP/IMPDP process instead of Upgrade process.

    Can i do the below steps,
    Step 1. Install server database
    Step 2. I can take backup from (Using EXPDP or advice me which one will be good)
    Step 3. Restore into (Using IMPDP)

    Are you agree this? If so, can you please advice me to where can i download server edition (32 & 64 Bit, If you provide, it will be great).

    Thank you so much for your time.


  11. Hi Mike,

    According to the Oracle Database upgrade from to

    I haven’t applied any patches according to the article "Things to Consider Before Upgrading to to Avoid Poor Performance or Wrong Results" but we still encounter with the performance issues.

    Can you please advice? Thank you.

  12. Jojabar,

    please open an SR and deal with Oracle Support. I can’t solve performance issues blindly. I’d recommend you instead. Just saying …


  13. Hi Mike,

    We are having one Oracle database using for ERP application. The current version is Standard Edition one on RHEL 5.4 . We are facing severe performance issue since last few months. As per one of the DBA, our DBA team has done some changes in DB level parameter. The current DB size is 300 GB. The PGA size is 4G, SGA Size is 25G. The server Memory is 32 GB.Processor Xeon 2.13GHz 1CPU 8 cores. HDD configuration is IBM 500GB 7.2K RPM 6Gbp/s SAS 2.5" SFF Hard Drive HDD 42D0707 42D0708 Server.

    I will provide you statspack or any other DB parameter details if you need to analyze in detail to provide your feedback/suggestions.


  14. Jaykumar,

    please open an SR with Oracle Support – I won’t be able to assist you diagnosing performance issues with an Oracle 10.2 EBS database.


  15. JayKumar,

    Setting up SGA size of 25G with 32GB of physical memory isn’t a good practice, it will eat up CPU resources.. Thumb rule is to have around 40-60% of physical memory as SGA size… and another drawback in your setup is that you are on Standard Edition which doesn’t have some important performance and scalability features available in Enterprise Edition like Bitmap indexing, Automatic Workload Management,Client Side Query Cache and many other features. Consider to switch to Enterprise edition and tune the DB parameters as per the need.
    Else you can resize SGA as well as use Hugepages.


    • Well, you may please open an SR with Oracle Support. Let me say that this is somewhat expected as the change from Oracle to Oracle is a release upgrade (even though it sounds like a small patch step). During your tests you should have seen a large number of changes in Optimizer behavior already.

      I’d recommend you to do the bug step and move forward to Oracle instead. Oracle will go out of Waived Extended Support in 13 months – the time you need for testing and adjusting Oracle is exactly the same as you’d need for


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