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August 2010

Good OCP / bad OCP

For those contemplating launching a career in Oracle database administration, there are essentially three routes:

  • Oracle education and certification (OCP)
  • Third-party educational programs (University and private training)
  • Self-directed study and experimentation

Most entering into the field assume that to be employable, they must become an Oracle Certified Professional (OCP).  They might be surprised to know that most working Oracle professionals do not have this certification.

Although having an OCP is a nice way to show a prospective employer that you are serious about your profession, this certification has never gained the kind of universal traction that Microsoft’s MCSE has.  There are a few reasons for this:

  • Oracle education has not matched curriculum with business needs
  • The Oracle certifications are very expensive
  • Generally, companies hire Oracle DBAs based on technical merit, not paper certifications

Oracle’s classes and exams emphasize memorization of syntax and specific values and settings, instead of broader concepts.  The kind of minutia that must be retained to pass an OCP exam is easily referenced day to day in the Oracle manuals.  Senior professionals in our field frequently do not know specific syntax and parameters.  What makes them senior is their broader, holistic understanding of Oracle systems, and the ability to solve problems.

The OCP certification costs over $2000 and exposes candidates to a minimum amount of practical hands-on experience.  Candidates must attend just one 5-day class in person or on-line and pass two exams to complete the program.  Needless to say this does not prepare anyone to face the real-life challenges of managing enterprise production systems.  It simply graduates people skilled at memorization and test taking.

More and more, the meritocratic culture of the Internet has pervaded hiring strategies for Oracle professionals.  That means that a person who has a broad and holistic knowledge of systems, and can ace a phone screen, is more valued in hiring decisions than someone who simply boasts an OCP credential. Interviewers are much more likely to ask, “How would you deal with the following scenario…?” rather than “What is the exact syntax for …?”

The value of private education and self-directed study

Many universities and private companies have crafted programs to provide education services that seek to fill the void left by Oracle University’s lack of practical orientation.  These programs emphasize hands-on lab exercises, concepts and best practices.

Blue Gecko has taken a keen interest in one program at the University of Washington: UW Professional and Continuing education’s Certificate in Oracle Database Administration. This weekly three-hour night class runs from October 2010 through June 2011. Blue Gecko’s president, Chuck Edwards serves on the academic board for this program, and it is largely taught by… me!

Two things make the University of Washington program unique:

  • Each student maintains their own 64-bit Linux Oracle server on Amazon EC2 for the duration of the program, compliments of Amazon Web Services
  • I deliver the course simultaneously in person in downtown Seattle at the UW’s Puget Sound Plaza, and over the Internet via Adobe Connect.  This means that students from anywhere in the world can take the course by attending virtually.

Even with the benefit of a class like the UW certificate program, anyone serious about becoming an Oracle DBA must be self-directed, and engage in plenty of independent experimentation and study.  Oracle’s development license allows anyone to download their software and run it for purposes of independent experimentation. My course at the UW is designed to orient students so that they are prepared to build independently on the knowledge they gained in the course.  During the course, I assign independent projects and reading. The goal of the course is to prepare students to think critically and formulate intelligent solutions both on the job and in job interviews.

Being an Oracle DBA can be a lucrative and interesting career.  But trying to break in using the Oracle certifications may prove more challenging than some might expect.  Consider the third-party education route, combined with independent study for your best chance at professional success.

Related posts:

  1. Blue Gecko recommends the University of Washington Oracle Certificate program
  2. Oracle Education – Our First DBA Class!!
  3. How I got access to My Oracle Support (MOS) for US$2.67

Environment Variables in Grid Control User Defined Metrics

This post originally appeared at the Pythian blog.

Emerson wrote: “Foolish consistency is the hobgoblin of small minds”. I love this quote, because it allows me to announce a presentation titled “7 Sins of Concurrency” and then show up with only 5. There are places where consistency is indeed foolish, while other times I wish for more consistency.

Here is a nice story that illustrates both types of consistency, or lack of.

This customer Grid Control installed in their environment. We were asked to configure all kinds of metrics and monitors for several databases, and we decided to use the Grid Control for this. One of the things we decided to monitor is the success of the backup jobs.

It has gone really quiet!

Yes, it has, and I’m really sorry but at the moment all the blog writing has to take a lower priority. I am working very hard to finish my chapters of the upcoming  Pro Oracle Database 11g RAC on Linux, which turned out to be a lot more work than I expected. The last chapter I have to write from scratch is about ASM, and it’s again a meaty one. Luckily the first draft is complete and I sent it to Apress for review and the usual editorial work.

I so decided to quit my daytime job to focus entirely on the book, which I’d like to see released between Open World and the UKOUG conference this year.

Once completed, I intend to become a freelance Oracle database consultant, specialising on RAC (no surprises here!) and Oracle 11.2 upgrades. I am available from mid September (the first 4 weeks are already booked!) if you like-just contact me!

Partially Index a Table

Recenty the following question was posted on oracle-l (I paraphrase…):
With Oracle Database it is possible to create something similar to Teradata’s sparse indexes?
Since the question is an interesting one, I decided to write this short post.
First of all, I have to say that such a feature is not supported by the CREATE INDEX statement [...]

Oracle acquisitions

In this graphic of the size, type and timeline of Oracle acquisitions:

I played with the data a little myself. Unfortunately not as long as I would like since I was using Tableau and my Tableau license runs out today. Tableau was a fun way to play with the data, though I didn't find all the knobs and dials I wanted, but here is what I had so far:

_db_file_direct_io_count で安定稼動


_db_file_direct_io_count : Sequential I/O buf size

このI/O buffer sizeを最適化してからテストを再度行う:

db_file_multiblock_read_count = 64, _db_file_direct_io_count = 524288

db_file_multiblock_read_count = 128, _db_file_direct_io_count = 1048576
db_file_multiblock_read_count = 256, _db_file_direct_io_count = 2907152

Oracle’s next blockbuster deal…

I got an email today, which I think is for once a genuine one…beside that, just before Oracle Open World, its always interesting to guess about what Mr. Ellison is about to announce…

I have checked out the site/post and, besides the apparent ones (PR), I couldn’t find any hidden traps (always a bit, healthy I hope, paranoia on this kind of stuff).

From: Stephen Jannise
Sent: Tuesday 3 August 2010 19:57
To: Marco Gralike
Subject: Editorial question about your blog

Hi Marco,

I thought you would be interested in an article I’ve written about Oracle’s next blockbuster deal. The company’s surprising acquisition of Sun suggests that Oracle is willing and able to make major deals in unexpected areas. I’m interested to see where they go next, so I’m hosting a poll on my blog at:

I’ve presented a list of thirteen potential targets for readers to vote on. Rather than guess these targets at random, I’ve done some research into the past five years of Oracle acquisitions as well as studied the current market to make some educated suggestions about possible future acquisitions.

Responses are trickling in, so I’m reaching out to a few bloggers to spread the word and drive more responses. Would you mind posting a brief entry about this on your blog? I would really appreciate your help. Please let me know what you think.



Stephen said about his article in one of his emails to me:

Oracle 5 Installation Steps

While browsing my old pictures, I discovered two small directories with some installation snapshots I once made, because there is almost no info left about this topic (besides in people’s heads) I left it here for “past” reference…

Double click on it to go to the bigger “version” on Picassa.

Product Design : VST

I think the VST diagrams are powerful on their own but my original goal was to show the execution path on top of the diagram in order to look at to execution plans side by side and quickly see the differences which isn’t possible with textual explain plans. Here is an example of two explain plans in text and then graphically

This graphic was one of my attempts to show executions on top of the VST diagram, and I’ve been working with how best to show the order. Because the diagram layout stays the same, and the order is overlaid on top, it’s easy to compare them side by side. I can also see why original execution plan, on the left, was wrong. The original execution started at E which joins to C producing 198201422 rows (as seen on the join line), yet the query only returns 44,000 rows (not shown). Also table E has no filtering, really, since 99% of it's rows are returned after applying the filtering condition. The filtering is represented in blue to the bottom right of the table as a percentage of rows returned from the table. The query should start at A where there is 2% filter ratio. After starting at A we should join to C or B (which is a subquery) because the result set sizes are the smallest 85K and 642K respectively. Making this change (via hints) took this query from running over 24 hours to 5 minutes)

Designing VST diagrams has been fun exciting and challenging. I wonder if you can imagine this: Have you ever been rock climbing ? and I’m not talking about the gym, but out on real cliffs? If so you probably know that 99% of the time people use a route map that shows exactly where to go and that indeed there is a way to climb up and off the cliff and so you won’t get stuck halfway up with nowhere to go. Climbing these routes is super scary and exciting, but the amazing thing is someone climbed them without a map, not knowing if they would get up 1000 feet and find that there is no way to finish, and somehow have to get down, which might not even be possible given the gear . Seriously life threatening.

That’s what I think about writing a completely new way of tuning SQL. Of course it’s not mortally life threatening J, but years of my life and my job are on the line. I have no idea where the end is, or what all the road blocks will be. I certainly didn’t when I started but I’m far enough along to see that the diagrams provide powerful information rapidly to the user in an easy to understand graphic way. Graphics can be misused even abused resulting worse information instead of better, but when graphics are used well they are much more powerful than the textual quantitative data. The graphical diagrams are a great way to understand the relationships in the query faster than reading the query text. It’s sort of like looking at the Google map and seeing the route drawn verses having to read the directions. Both are important but I can understand the route on map much faster than the directions, though I might want to read the directions after reading the map. The map with the route though is often all I need.

I’m not able to store vast amounts of information and see all the permutations like some Oracle experts can. This can be a curse and a blessing. It’s a blessing because it makes me look for ways where I can understand the problem space with out having to buffer tons of information and such solutions are valuable to the general public. On the other hand its scary in that I don’t see all the possible problems, but that can be a blessing as well because I try to just concentrate on the solutions that have the biggest return, the biggest bang for the buck , the issues that can be most easily solved, instead of getting distracted the overwhelming possibilities and issues.

In some ways the SQL optimization space seems overwhelming and in others ways it seems really small. I think that VST diagrams will help make the problem space seem much smaller, manageable and understandable as the VST diagrams mature.

It’s the End of the World As We Know It (NoSQL Edition)

This post originally appeared over at Pythian. There are also some very smart comments over there that you shouldn’t miss, go take a look!

Everyone knows that seminal papers need a simple title and descriptive title. “A Relational Model for Large Shared Data Banks” for example. I think Michael Stonebraker overshot the target In a 2007 paper titled, “The End of an Architectural Era”.

Why is this The End? According to Michael Stonebraker “current RDBMS code lines, while attempting to be ‘one size fits all’ solution, in face, excel at nothing. Hence, they are 25 years old legacy code lines that should be retired in favor of a collection of ‘from scratch’ specialized engined”.