That’s Me

Gavin Soorma
  • Oracle Certified Professional
    • 7.3, 8i, 9i,10g, 11g
  • 11i Apps DBA OCP
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  • 10g RAC OCE
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  • Certified GoldenGate Implementation Specialist
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  • 10g OCM
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  • 11g OCM
    •

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    Using DBMS_ADVANCED_REWRITE with an HINT to change the execution plan

    In one of my earlier posts, I had illustrated a use case of DBMS_ADVANCED_REWRITE and its use in cases where we cannot change the code, but can still influence and change the way the optimizer executes the same SQL statement.

    In case of many vendor provided and packaged applications, we do not have access to the SQL code and we cannot rewrite the SQL statements.

    So there could be cases where even though indexes are present on the table, they are not being used by the optimizer and one way we can force the optimizer to use an index is via the INDEX hint.

    So how we change the execution plan of the optimizer for a particular statement without changing the original SQL statement that the application is executing?

    We do it using the powerful new feature introduced in 10g called DBMS_ADVANCED_REWRITE or “tuning without touching the code”.

    To illustrate this, let us create

    Continue reading Using DBMS_ADVANCED_REWRITE with an HINT to change the execution plan

    June 29th, 2011 | Category: Administration, Performance Tuning | One comment

    Upgrading Enterprise Manager Grid Control 10.2.0.5 to 11g

    Purpose:

    This note describes the steps taken to upgrade an existing 10.2.0.5 Enterprise Manager Grid Control environment hosted on Red Hat Linux 5.5 to Enterprise Manager 11g (11.1.

    The upgrade of the 10.2.0.5 OEM broadly involves the following steps

    • Install the Oracle 11g Release 2 database software. This will be used for the repository database.

    • Install Oracle 11g Release 1 WebLogic Server

    • Upgrade the 10.2.0.5 repository database to 11g Release 2

    • Install the 11g OEM Grid Control software and upgrade Management Server (OMS) from 10g to 11g.

    • Upgrade existing 10g management agents to 11g

    The following tasks can be performed while the 10g Grid Control environment is up and running.

    • Install the Oracle Database Software – 11g Release 2

    • Install the Oracle 11g WebLogic Server (10.3.2)

    • Install the Java Runtime Environment 1.6 Update 18

    ….
    ……..

    Download this note ….

    June 17th, 2011 | Category: Administration, EM Grid Control | Leave a comment

    Upgrading to 11g Release 2 and DST Updates

    When performing an upgrade to Oracle 11g Release 2, we would need to take into consideration if there are any DST (Daylight Saving Time) implications which could be the vase in case we have application tables using the datatypes TIMESTAMP WITH TIME ZONE and TIMESTAMP WITH LOCAL TIME ZONE.

    Oracle 11.2.0.2 uses Time Zone version 14 and 11.2.0.1 use Time Zone version 11. In Oracle 10.2.0.4 the Time Zone is 4 and if we are planning to upgrade from 10.2.0.1 to 11g Release 2, then we need to first patch the database to at least version 10.2.0.2 before we can attempt a direct upgrade to 11g Release 2.

    One of the good new features in 11.2.0.2 Database Upgrade Assistant (DBUA) is that DBUA would automatically upgrade Time Zone to version 14 if you checked “Upgrade Timezone Version and TIMESTAMP WITH TIME ZONE data” box as shown below.

    If we are using

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    June 16th, 2011 | Category: Administration, Oracle 11g release 2 | Leave a comment

    Capturing GoldenGate Before Images Using GETUPDATEBEFORES

    Oracle Goldengate provides a mechanism for capturing the before images of the row before any modifications were made to the row. Something very similar to the undo segment concept of the Oracle database.

    This can be done using the GETUPDATEBEFORES parameter in either the Extract or Replicat parameter file which will essentially control whether or not the before images of updated columns are included in the records which are processed by GoldenGate.

    We can use this not only for conflict resolution purposes but more importantly by comparing before and after images, we can identify net results of transactions, perform some delta calculations and also to maintain a transaction history.

    Let us for example see a case where we are storing some currency exchange data in a table which is naturally subject to changes on a continuous basis because the currency rates naturally fluctuate over time.

    We would like to maintain a history of

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    June 9th, 2011 | Category: GoldenGate | Leave a comment