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January 2015

Working With AWR Reports From EM12c

I’ve had a recent request to write an update on working with AWR reports, so as promised, here it is!

The Automatic Workload Repository

The Automatic Workload Repository, (AWR) was one of the best enhancements to Oracle back in release 10g.  There was quite a goal put in front of the development group when they were asked to develop a product that:

Data Center of the Future – now



photo by youflavio

In a recent blog post Eric D. Brown defined an Agile Data Center as

#777777;">An Agile Data Center is one that allows organizations to efficiently and effectively add, remove and change services at the speed of the business, not the speed of technology – Eric D. Brown

In follow up post he said that a Agile Data Center could be implemented by Software Defined Data Center (SDDC) for example using machine virtualization to spin environments up and down.

Restrict the query optimizer through OPTIMIZER_FEATURES_ENABLE and Top-Frequency/Hybrid Histograms

To make upgrades easier, I regularly see people considering disabling query optimizer features by setting the OPTIMIZER_FEATURES_ENABLE initialization parameter to a non-default value. My general opinion about this “habit” is summarized in TOP with the following two sentences:

Changing the default value of the OPTIMIZER_FEATURES_ENABLE initialization parameter is only a short-term workaround. Sooner or later the application should be adapted (optimized) for the new database version.

Finding Oracle VM Manager Core Management Port After OVM Manager Installation

Recently I was working on integration of OVM Manager with Oracle EM Cloud Control 12cR4 and I had to enter the "Oracle VM Manager URL" a.k.a. as "Core management port" which is reported at the end of OVM Manager installation. The default value for this port is 54321. As I was not in position to get this post-installation report because the installation was performed by another company, I had to find out the right port. The definition should be entered in the form: tcp://:
. by Clive Bostock


#555555; padding-left: 30px;">This is a reposting of an old blog post that was on but is no longer accessible

#555555; padding-left: 30px;">More trace file analyzer tools at  #2970a6;" href="">

#555555; padding-left: 30px;">Related blog post: Oracle “Physical I/O” ? not always physical with a 10046 parser specifically for I/O and readme

An Oracle Instance is Like An Upmarket Restaurant

I recently did an Introduction to Oracle presentation, describing how the oracle instance worked – technically, but from a very high level. In it I used the analogy of a restaurant, which I was quite happy with. I am now looking at converting that talk into a set of short articles and it struck me that the restaurant analogy is rather good!

Here is a slide from the talk:

Simple partial overview of an Oracle Instance

Simple partial overview of an Oracle Instance

Enterprise Manager and Services, Part I

The term “Service” is used to represent numerous objects within Enterprise Manager 12c.  Although the most common reference to the term is related to the Oracle Management Service, (OMS), in this blog post, we are going to drill down and refer to all services identified in the drop down menu from Targets, Management Services and Repository.

Put Delphix on your laptop at Oracle Jan 28 !



Create an army of clone databases and applications in minutes


Tomorrow Jan 28 we will be installing Delphix on people’s laptops at the BIWA conference at Oracle conference center at Oracle head quarters in Redwood Shores.


Using Hyphen In OS Username Or ORACLE_HOME Path in Oracle 12c Database Installation Will Make You Cry

Recently I was involved in an upgrade project on Linux platforms to Oracle 12c ( and the customer wanted to name the owners of the Oracle SW distribution according to their company standard. So instead of using "grid"  and "oracle" OS account names they wanted to have the names which would start with "svc-" and continue with unique non Oracle standard name for either grid infrastructure or database software. Besides using this names as owners of grid and database software we used them also in the names of the GRID_HOME and ORACLE_HOME directories according to Oracle OFA suggestion.