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Advanced Methods for Managing Statistics of Volatile Tables in Oracle (Hotsos...
Thanks to all who attended my presentation at Hotsos 2012. You were a great audience with insightful questions and relevant comments. Here is my presentation along with the white paper. The code for...
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Hotsos 2012 – the benefits of a discussion with a really knowledgeable audience
After a short conversation with Alex Gorbachev, I realized that maybe I should have added some implementation details about the “two-phase removal of data” approach for reducing table...
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Finally! Something on this blog that can really save you money.
No, I am not kidding! As you may have heard, News America Marketing just launched a free couponing app for the iPad called SmartSource Xpress. We’re very excited about our revolutionary new product and...
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Cardinality feedback for queries that use volatile tables with locked...
As if dealing with volatile tables alone is not complicated enough, in Oracle 11gR2 we also have to consider how the new cardinality feedback feature (on by default) would affect us. While there is a...
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Oracle Enterprise Manager Oracle Enterprise Manager Cloud Control 12c is...
There are many great features in the new OEMCC 12c, and probably as many great presentations or blog posts about them. This post is not about a particular new feature, it is about the...
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Security considerations and challenges when querying OEM repository tables/views
OEM utilizes virtual private database (VPD) policies in addition to the standard database privileges and roles. That means that the DBA cannot just give privileges on OEM objects to a DB user, it has...
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How to Use the New OEM 12c Metric Extensions to Enforce Enterprise-Wide...
Oracle Enterprise Manager’s User-Defined Metrics (UDMs) were a very suitable vehicle for enforcing enterprise-wide policies. My NYOUG 2011/VirtaThon presentation and white paper contain a comprehensive...
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NYOUG Sept. 2012 – Reduce Your Disk Footprint by Sharing Read-Only Tablespaces
Thanks to all who attended my presentation (Reduce Your Disk Footprint by Sharing Read-Only Tablespaces) at NYOUG. We had a great discussion! The Power Point slides are here – I did some animation, so...
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“ORA-20008 Number of extensions …” – what to do about this unnecessary error
There are times when Oracle puts restrictions to save us from our own bad practices. For instance, committing in triggers is forbidden so we do not make a mess, among other things. And then there is...
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Same SQL_ID, same execution plan (SQL_PLAN_HASH_VALUE), greatly different...
A query runs fine in one environment, but is terrible in another. The usual suspects – different execution plan, hardware issues, etc are ruled out. The next step is to look at the actual execution...
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More Useful OEM Repository Queries
I already included a number of queries against the OEM repository in my presentation. Now, I would like to add two more. The first query shows an approximation of the average and max CPU utilization...
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Hotsos 2013 and some more useful OEM queries
Busy preparing for Hotsos 2013. My presentation this year is “Working with Confidence: How Sure Is the Oracle CBO about Its Cardinality Estimates, and Why Does It Matter?” I know it is a mouthful. The...
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Dependent/correlated sets in Oracle – definition, problems and solutions.
To better understand dependent/correlated sets, let’s take a brief look at dependent/correlated columns. Oracle works under the assumption that the data in each column is independent. If an equality...
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Hotsos Symposium 2013
It was a great pleasure presenting at Hotsos. Thank you for attending my presentation – your comments and questions were quite insightful. I owe a bit more explanation to the lady who asked about the...
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Hotsos Symposium 2013 continued
During my presentation at Hotsos 2013, an attendee questioned my statement that each filter/selection predicate contributes to the overall cardinality error. She believed that only the predicate with...
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Measuring the Benefits of Database Virtualization/Thin Provisioning Solutions
Overview Database virtualization and thin provisioning are new and powerful ways to share/reuse storage among non-production database copies. Solutions for reducing the disk footprint of non-production...
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Some more useful undocumented OEM 12c repository tables/views
As mentioned in a previous post, MGMT_ECM_HW contains a wealth of information about hosts in OEM. The problem is that CLOCK_FREQ_IN_MHZ column in MGMT_ECM_HW is not properly populated. All hosts had...
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Oracle 12c Adaptive Execution Plans – Do Collected Stats Still Matter?
Adaptive execution plans is one of the most exciting new features in Oracle 12c. Now, in Oracle 12c, the optimizer can pick the join method based on the actual amount of data processed, rather than the...
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NYOUG Fall General Meeting (2013)
I am excited to present at the NYOUG Fall General Meeting (2013). I’ll be speaking about volatile tables in Oracle. They are not common, yet they can wreak havoc on the database performance when...
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New York Oracle User Group (NYOUG) Fall 2013 Conference
Thanks to all who attended my session at NYOUG. As usual, it was a great experience! Download the presentation here and the white paper here. You can also download the spec here and the body here of...
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