Automatically Grouping Query Results into Row Sets of a Specific Size

I came up with a simple formula a couple of days ago that will automatically determine which result set  a row belongs in if the results of the query need to be grouped in specific numeric sets of rows (such as sets of five rows, or sets of 10 rows, etc ..) for retrieval and display in an object such as a table widget on a web page.  These would be the sets of rows that are displayed by the ‘Next’, ‘Last’, and ‘Previous’ buttons (or arrows) on the widget.  The formula can  be applied directly in the (more...)

Finding the Best Match With a Top-N Query

There was an interesting index related performance problem on Stack Overflow recently. The problem was to check an input string against a table that holds about 2000 prefix patterns (e.g., LIKE 'xyz%'). A fast select is needed that returns one row if any pattern matches the input string, or no row otherwise.

I believe my solution is worth a few extra words to explain it in more detail. Even though it’s a perfect fit for Use The Index, Luke it’s a little early to put it as an exercise there. It is, however, a very good complement (more...)

Configure Oracle dbconsole…

| Sep 28, 2010
For a 10g database I wanted to check something in the database console. When trying to start this console, I received the following error : OC4J Configuration issue. Oracle/ora102/oc4j/j2ee/OC4J_DBConsole_.local_ not foundThe ORACLE_HOME is a shared one, meaning different databases use the same ORACLE_HOME. So, because of this there were some other directories but not the one I needed. I

OTN interview of Oracle APEX PM David Peake

Oracle Application Express product manager David Peake takes questions from the Oracle Technology Network's Justin Kestelyn in archive of a live Oracle world video cast. See it here.

Where is Oracle’s Heart?

A good thing about Larry Ellison’s keynotes is that the rambling, free-form style gives you a good impression of Oracle’s focus – something that’s not in the slides or the press kit.

On Wednesday, Larry spent all of his allotted time (and more) speaking about his favorite new box, the (more...)

Oracle Closed World and Unconference Presentations

There are so many things to blog about these past few days. That is mainly about the cool stuffs around OCW and OOW, sessions that I have attended (OCW, unconference, OOW), plus the interesting people that I’ve met on various areas of expertise.. So I’ll be posting some highlights (and a lot of photos) on the next posts.

Last Monday (Sept. 20) I was able to present at the Oracle Closed World @ Thirsty Bear. The full agenda is here

I did my presentation after Tanel’s live hacking session. There were 30 (+-5) attendees and (more...)

Generating A Gap-free Series Of Numbers — Not Always A Problem

| Sep 24, 2010
Well, it’s happened again. Someone has asked how to implement a requirement to generate a gap-free series of numbers and a swarm of nay-sayers have descended on them to say (and here I paraphrase slightly) that this will kill system performance, that’s it’s rarely a valid requirement, that whoever wrote the requirement is an idiot [...]

SQL Developer 3.0 demonstrated at OOW

The SQL Developer development team is at the demo pod in Moscone West and has been busy showing off the latest (yet to be released) version of SQL Developer. SQL Developer 3 features an all new graphical query builder, a scheduler interface, data import wizards, improved data grids, basic DBA (more...)

Finding the Cost of an Index

Building and maintaining an index structure can be expensive, and it can consume resources such as disk space, CPU, and I/O capacity.

According to the Oracle Database Performance Tuning Guide 10g Release 2 (10.2): "...each index maintained by an INSERT, DELETE, or UPDATE of the indexed keys requires about three times as much resource as the actual DML operation on the table. What this means is that if you INSERT into a table (more...)

Working Around an Internal Error Based on Source Mnemonics

| Sep 23, 2010
My frenzied hacking through the unexplored territory of Expression Filters was derailed (to mix my metaphors) by an internal error when using the Evaluate() function in a rather complex query that uses an inline view, analytic functions etc.. The following was extracted from the alert log: ORA-07445: exception encountered: core dump [kkqsCkLegalEqvExpCB()+199] [SIGSEGV] [Address not [...]

Oracle BI Publisher 11g

Oracle open world (OOW) is great opportunity catch up on new database and database tools technologies. Yesterday, my highlight was seeing an in-depth presentation of Oracle BI Publisher 11g. I was blown away by the clean and remarkably advanced browser based user interface. The ability to define pixel perfect reports (more...)

finally back!

A thousand apologies for the lack of news. Well, it's been a wild ride since the last post, way back in March! On the work front:We finally finished the new DR site. And it's all working fine. Not just that, though: a LOT more!If you go here you'll see in the files area a presentation on how we do SAN-driven DR database replication. It works with SE Oracle, EE, or any other kind of (more...)

Enhancement Requests and Bugs for Oracle eBusiness Suite

From time to time I create enhancement requests or bugs, commonly on Oracle eBusiness Suite. Additionally I come across enhancement requests that I think deserve more visibility. This page is dedicated to that cause. If you have an Oracle Enhancement Request (ER) or Bug you would like to raise the visibility on, please feel free to comment or contact me.
If you like the looks of one of the Enhancement Requests noted below, log a (more...)

If your at OOW 2010 don’t miss Tom Kyte on What’s new in DB App Dev

Most know Tom Kyte from (, and from countless presentations he has delivered world wide. Many people may not know that Tom was also instrumental in both WebDB and Oracle Application Express coding parts of both products and mod_plsql. So if your in OOW in SF this week, (more...)

Oracle SQL Developer Data Modeler is now a no cost (free) product

In an effort to bring world class database data modeling to the Oracle database developer community SQL Developer Data Modeler is now a free product. Support is provided with your database support, making SQL Developer Data Modeler just like SQL Developer; in that they are both no cost. You can (more...)

I’m giving the APEX 101 presentation at Oracle World Monday Sept 20, 2010

I will be giving an intro to Oracle Application Express (APEX)
Session ID: S317042
Monday 20-SEP-2010 12:30 pm – 1:30 pm
Moscone South, Room 306
If your at OOW and want to learn what Oracle APEX is all about you may find this session interesting.

EclipseLink at Open World/Java One/Oracle Develop 2010

The EclipseLink project will be well represented this year at Java One and Open World. If you are here attending the shows then I recommend you attend some of our sessions or drop by and visit us at the exhibition booths.

ID#: S314492
Title: Java Persistence API (JPA) 2.0 with EclipseLink
Date: 20-SEP-10
Time: 16:00-17:00
Hilton San Francisco, Golden Gate 4/5

ID#: S317452
Title: Advanced Enterprise Persistence
Date: 22-SEP-10
Time: 10:00-11:00
Hotel Nikko, Nikko Ballroom II

S314491: Effective XML: Leveraging JAXB and SDO
Date: 22-SEP-10
Time: 13:00-14:00
Hilton San Francisco, Yosemite A

S313434: Java Persistence API Futures BOF
Date: (more...)

Stupid Yahoo Mail

| Sep 20, 2010
I just browsed my Yahoo spam folder and found an email purporting to be from an ex-work colleague. It was sent to a bunch of other ex-colleagues as well and contained a link to what looked like a site for selling fake ED pills. I replied to the colleague to say, “Hey looks like you’ve [...]

A Cause of ORA-38435 in Evaluate()

| Sep 20, 2010
I’m part way through an implementation of some ELT code that uses expression filters to parse records and assign zero-to-many “inboxes” to each row, and as is often the case with the less well-explored parts of the system it often feels like I’m hacking through the undergrowth in unknown territory. Under such conditions it’s not [...]

OOW 2010 – the highlights

I started my week with a blast by sky diving at Parachute Center – Sacramento, it was an awesome experience!

Then we went to Redwood Shores to check out the Oracle office

Then headed back to the Moscone area to register and attend the sessions

On the way to the 3rd floor to get the conference materials I saw a familiar face.. yeah it’s my friend Craig Shallahamer! finally we’ve met.. and we had a long talk & catching up about performance related stuff before his talk about troubleshooting “free buffer waits” at 3pm

On the “RAC customer panel” (more...)