News, views, tips and tricks on Oracle and other fun stuff

When Versioning Support Interferes With Saving Your Relational Model

Oracle SQL Developer Data Modeler icon To reverse engineer an existing database into a relational model, I used SQL Developer Data Modeler, a free data modeling and database design tool from Oracle.

I had a problem with the tool. I could not save the model. It appeared to be saved but when I reopened the .dmd file, the relational model was nowhere to be found.

I tried all kinds of combinations on my Windows 7 64-bit laptop, like using JDK 6 vs. JDK 7, 32 bit vs. 64 bit versions, etc. No luck.

Then I stumbled upon this Oracle Forum thread while searching for a solution online. The poster suggested that enabling support for version control in the tool solved the issue.

I have TortoiseSVN installed on my laptop and use it to interface with a subversion repository.

I had versioning support disabled in SQLdev Data Modeler.

Following the hints in the forum post, I enabled it (Tools > Preferences > Extensions > toggle Versioning Support). Restarted SQLdev Data Modeler, and voila! I can now save my relational models!

There was no way I could have guessed that versioning support was interfering with saving relational models. I am guessing this is a bug.

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SQL Plan Stability and CBO Statistics Myths Busted

Carlos Sierra:

Since lack of Histograms or freezing CBO Statistics do not guarantee Plan Stability, do not rely on these two myths. If what you are looking for is Plan Stability use then SQL Plan Management available since 11g or SQL Profiles available from 10g.
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Logger: a PL/SQL Logging and Debugging Framework

Martin D’Souza:

Logger is a PL/SQL logging and debugging framework. It’s used in many organizations to instrument code in their Oracle applications. Tyler Muth created Logger a few years ago and has since released several upgrades, the last being 1.4.0. After some great feedback, I’m pleased to announce that we’ve just launched Logger 2.0.0 Beta.

Instrumentation, logging and debugging utilities are essential in any PL/SQL development project.

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Not a Fan of Public Synonyms, Here is Why

Tom is not not a fan of public synonyms, here is why:

  • public synonyms pollute the namespace.
  • public synonyms can lead to security issues.
  • public synonyms can lead to a maintenance headache.
  • public synonyms are public – no one owns them.

So, instead of public synonyms… Continue reading…

2 Comments | Filed in Oracle | Tags:

When You Should Consider Flash for Database Storage


If any of this is ticking boxes for you, it’s time to consider what flash could do for the performance of your database:
  • I/O wait times are high. Essentially we are looking for high latency from the existing storage system. Flash memory systems should deliver I/O with sub-millisecond latency, so if you see an average latency of 8ms on random reads (db file sequential read), for example, you know there is potential for reducing latency to an eighth of its previous average value.
  • I/O forms a significant percentage of Database Time. If I/O is only responsible for 5% of database time, no amount of lightening-fast flash is going to give you a big performance boost… your problems are elsewhere. On the other hand, if I/O is comprising a large portion of database time, you have lots of room for improvement.
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Oracle News Aggregator OraNA No Longer Powered by Google Reader

OraNA.infoYou probably heard that Google is going to shut down Google Reader (GR) on July 1st, 2013.

There are many theories, speculations and analysis as to why Google took the decision to kill Reader.

To me GR was not just a place I visit several times daily to get my dose of fresh news, it was also the backend feed aggregation engine that has powered since 2006.

With GR going away soon, I have been working over the past several days to detach it from OraNA.

I’m glad to report to you that the migration off of GR is done. OraNA now aggregates all of its syndicated feeds via its own feed aggregation engine.

OraNA has been operating since the beginning of 2006. In the process of updating it, I took the opportunity to do spring cleaning on the blogs that it aggregates.

Blogs that no longer exist have been deleted from the aggregator.

Blogs that still exist but have had no new posts since January 2012 are no longer aggregated by OraNA.

I was surprised at the number of blogs that fell into the two categories above.

The number of aggregated blogs fell from 508 to 323 (plus the feed).

Here is a live list of all the blogs that OraNA aggregates.

I guess the enthusiasm for long form blogging has fizzled out over the years. Lazy bloggers (including yours truly) find it much easier and quicker to “micro” blog using Twitter, Facebook or Google+.

On a personal note, I have moved my daily dose intake of news from GR to Feedly.

2 Comments | Filed in Oracle | Tags: , ,

SQL Developer/APEX Listener Bug and The Power of Social Networking in Action

Have you installed or recently upgraded to Oracle APEX Listener 2.0? Have you used SQL Developer 3.2 to manage APEX Listener settings? If you answered yes to both questions then you are in for an unwelcome surprise.

The surprise is that you’ll get a “500 – Internal Server Error” whenever you upload a file via any of your APEX apps or import files via the APEX Application Builder.

Kris Rice responded to my tweet almost immediately.

The problem was a bug in the way SQL Developer uploads APEX Listener settings to the server.

This Oracle forum post describes how to reproduce the bug and the workaround to fix it.

Kris quickly put a fix together and checked it in for the next patch.



If you are still hesitant to join Twitter, I hope that this post has given you an incentive to join this growing social network. Many Oracle employees, like Kris, are active on Twitter and listening to people like you and me who use their products on a daily basis.

To make it easier for you to follow Oracle people on Twitter, I have created this Oracle list. The list occupies a permanent column on my Tweetdeck stack.

1 Comment | Filed in Oracle | Tags: ,

Event-based Scheduler Jobs and Oracle Streams Advanced Queuing: A Powerful Combination


An external or internal application wants to send inbound data to your Oracle database, like for example a purchase order or a receivable invoice. You want to consume this data in real time.


The version of your Oracle database is 11gR2 or above. The only “tool” you have is the Oracle database, i.e. you do not have any middleware (like SOA suite) installed. The external or internal application can connect to your Oracle database.


Use Oracle Streams Advanced Queuing (AQ) for messaging. Use an event-based scheduler job for real time data consumption. Both are standard features of the Oracle database.

Implementation Steps:

The following is a fully functional example of the solution, starting from creating a new database user and ending with consuming the message in the database.

Continue reading…

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Video Montage of Oracle ACE Directors

Todd Trichler (@otnTodd) created a video montage of a bunch of Oracle ACE Directors. Ever wonder what an Oracle ACE Director is like? Check out the video below. I make an appearance at 4:02 minutes.

Bonus footage of the Oracle ACE Program wranglers Vikki Lira and Lillian Buziak (@oracleace) discussing the program.

Continue reading…

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Oracle OpenWorld 2012 – Latest and Final News (Oct04)

Selected tweets, videos and photos from the last two days of Oracle OpenWorld 2012:

Continue reading…

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