Quiz night

Prompted by an email from Yves Colin (who’ll be presenting on the Tuesday of UKOUG Tech14) I was prompted to dig out a little script I wrote some years ago and re-run an old test, leading to this simple question:  what’s the largest size array insert that Oracle will handle ?

If you’re tempted to answer, watch out – it’s not exactly a trick question, but there is a bit of a catch.

 


Using APEX to Create a Mobile User Interface for Enterprise Manager 12c

On November 11th, I will be presenting at Oracle Day Istanbul. My presentation will be about creating a mobile interface (a simple application) using Application Express to access Oracle Enterprise Manager repository views (and some procedures) to manage incidents and problems. I know that there’s already an application for idevices, but my application is a web application designed for mobile (thanks to APEX), so it’s compatible with all devices. The sessions are short, only 30 (more...)

AUSOUG Conference Perth, November 2014

What a great conference – there’s been a lot of praise for the organisers and all the speakers. I haven’t missed a conference since I started 15 years ago, and I hope it keeps going (in one form or another) for a long time to come.

This year I attended the following sessions (some titles changed for effect):

Björn Rost – 12c for DBAs and Developers; FDA (time to drop those journal triggers)

Scott Wesley – CSS & (more...)

Guest template Oracle Linux 6.5 available on Exalogic

When Oracle Exalogic is delivered in you data center and you implemented Exalogic as a virtual platform, the Exalogic Guest Base Template (EGBT) is based on Oracle Linux 5.8. On Exalogic you can update the template to Oracle Linux 5.10. As of 21 october the new Exalogic base template is on Oracle Linux 6.5. The Oracle Linux 6.5 template for virtual platforms is available for download via Patch 19376316. The new template (more...)

Cardinality Feedback

A fairly important question, and a little surprise, appeared on Oracle-L a couple of days ago. Running 11.2.0.3 a query completed quickly on the first execution then ran very slowly on the second execution because Oracle had used cardinality feedback to change the plan. This shouldn’t really be entirely surprising – if you read all the notes that Oracle has published about cardinality feedback – but it’s certainly a little counter-intuitive.

Of course (more...)

The Importance of Backups (A Cautionary Block Recovery Tale)

Just wanted to share a quick story with everyone. As I was in the airport waiting to fly to Oracle OpenWorld this year, I noticed a flurry of emails indicating that part of our storage infrastructure for our standby production database had failed. Long story short, my co-workers did a brilliant job of stabilizing things and keeping recovery working. However, we ended up with more than a few block corruptions.

Using the RMAN command "validate (more...)

ECO 2014 Slides

Just a quick note that I posted slides for the 2 talks I did at ECO in Raleigh this week:

Keynote: Creative Problem Solving (for Oracle Systems)

In-Memory In Action (without Tanel Poder) :)

Great crowd. I really enjoyed myself.

Note: You can also find other presentations on my Whitepapers/Presentations page via the link at the top of the screen.

How to Find Blocking Sessions in Enterprise Manager Cloud Control 12c

My friend Franck Pachot noticed that EM12c doesn’t show the blocking sessions across all RAC nodes. Let’s check if we can find them using EM12c. I have connected to first node of our RAC database, created a sample table, inserted a row, committed, and then deleted the row. While the session is open, I opened another terminal, connected to second node and tried to delete the rows in same table so my second session started (more...)

Oracle Enterprise Manager 12c Command Line Interface is Available!

The new Oracle Enterprise Manager 12c Command Line Interface book is available via a number of locations, including Amazon and directly from Apress.  If you are an EM12c fanatic or just learning and want to learn more, consider the new book that will show you why the command line returns the DBA to the golden age, empowering Enterprise Manager to script and enable tasks at a global level!

9781484202395HiRes



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Interesting Oracle Syntax Error

As shared by a well known Oracle and Big Data performance geek!

SQL> ALTER SYSTEM SET inmemory_size = 5T SCOPE=spfile;
ALTER SYSTEM SET inmemory_size = 5T SCOPE=spfile
*
ERROR at line 1:
ORA-32005: error while parsing size specification [5T]


SQL> ALTER SYSTEM SET inmemory_size = 5120G SCOPE=spfile;

System altered.

:)

Upgrades

One of the worst problems with upgrades is that things sometimes stop working. A particular nuisance is the execution plan that suddenly stops appearing, to be replaced by an alternative plan that is much less efficient.

Apart from the nuisance of the time spent trying to force the old plan to re-appear, plus the time spent working out a way of rewriting the query when you finally decide the old plan simply isn’t going to (more...)

Reverse engineer and discover foreign keys with SQL Developer Data Modeler

Originally posted on HeliFromFinland:
You can easily document your database with Data Modeler: just reverse engineer the database with File-> Import -> Data Dictionary. But what if the database has no foreign keys? What’s the point of documenting then? Just tables that has nothing to do with each other…. Well, Data Modeler can help with…

Adding NOT NULL Columns with DEFAULT values

In Oracle, if we add a column to a table which is NOT NULL, we are allowed to do it directly, in a single statement, as long as we supply a DEFAULT value to populate any pre-existing rows.
This would mean that every row in the table was updated with the default value. This could be a pretty nasty side effect, as lengthening every row in the table will inevitably lead to chained rows, and (more...)

Metric Thresholds and the Power to Adapt

Metric thresholds have come a long way since I started working with OEM 10g.  I remember how frustrating it could be if an ETL load impacted the metric values that had to be set for a given IO or CPU load for a database when during business hours, a much lower value would be preferable.  Having to explain to the business why a notification wasn’t sent during the day due to the threshold (more...)

OT: Oracle Trivia Quiz

All the answers to the quiz are in the November 2014 issue of the NoCOUG Journal . I am the editor of the NoCOUG Journal. What’s NoCOUG, you ask? Only the oldest and most active Oracle users group in the world. If you live in the San Francisco bay area and have never ever attended a NoCOUG conference in the last 28 years (that’s how long NoCOUG has been around), please contact me for a free (more...)

Structured XML output from Oracle SQL query

Got an interesting question today: There are tables TABLE1, TABLE2 and a junction table that joins them called JUNCTABLE. Need the following output as XML


  
  


  
  

I know the output could be aggregated using XMLAGG, but I have never looked into how to format the tag names and attributed in the output like requested.

Data in my very simplified sample tables:

SQL> select * from table1;

        ID
----------
         1
         2
         3

SQL> select * from table2;

         (more...)

Oracle Trivia Quiz

All the answers can be found in the November 2014 issue of the NoCOUG Journal. Which executive vice-president of product development at Oracle began as the PL/SQL product manager? (page 23) Which senior vice-president of server technologies at Oracle wrote the B-Tree indexing code back in the day? (page 23) What is the evil twin […]

SOA Suite 12c: Bulk Fault Recovery

In earlier versions of the Enterprise Manager it was already possible to recover faulted instances of webservices. Like for instance when a service that the instance depends on is down, the instance will throw a fault and stop processing. When the underlying service is up again, you could go back to the faulted instance and use recovery to have it continue from the step it faulted on.

Now with the introduction of 12c the Error (more...)

The Hitchhiker’s Guide to the EXPLAIN PLAN Part 26: Answers to the Final Exam! (Part IV)

The answers to the third problem in Part 22 of this series “We Don’t Use Databases; We Don’t Use Indexes.”(read more)

Results of the NoCOUG SQL Mini-Challenge

As published in the November 2014 issue of the NoCOUG Journal The inventor of the relational model, Dr. Edgar Codd, was of the opinion that “[r]equesting data by its properties is far more natural than devising a particular algorithm or sequence of operations for its retrieval. Thus, a calculus-oriented language provides a good target language […]