Starting young

I think this is seriously awesome. This group of students are using the Beginning Oracle SQL book I co-authored in their high school Oracle class. Yes, that's right. I said high school Oracle class. I just recently became aware that a teacher at this particular Colorado high school has been including Oracle curriculum in her computer science class for a decade or so. Apparently, these kids are using the book to help them prepare for the Oracle SQL certification exam.

It amazes me that these high school students are getting exposed to Oracle this early. Not only are they getting exposed but they are learning enough to take (and pass) the Oracle SQL exam. I even heard there have been some students over the years who have completed their DBA certifications as a result of this program. Heck, when I was in high school I had never touched a computer. Of course that was back in the stone age before computers were as prevalent as bottled water (which also wasn't really around when I was a kid)!

The fact that this educator has put this in her curriculum and continued to do so for so long is something special. She also takes some of her students to the RMOUG (Rocky Mountain Oracle Users Group) Training Days each year as well. That shows real interest in the kids and a desire to let them see how their education is put into action in the real world. I think such an experience would have had a huge impact on me at that age.

So, hats off to this group of students and their teacher. Here's to all of them and the next generation of Oracle professionals!

What's important

In reviewing my blog activity over the past few years, I noticed that the first two years I had the blog I averaged about one post per week. The next year, my posts fell off to about one per month. Then last year, I only had 3 posts! Talk about decline!

I want to revitalize my blog and post 1-2 times per month. Given my blogging history, I realize this is a big change to commit to. I think part of me being successful is going to hinge on understanding where making time to blog more regularly fits into my life. My lack of posts hasn't been due to a lack of material or ideas...I have tons of those. My passion for work and interest in continuing to learn and grow professionally is as strong as ever. But I've found that almost everything has taken a back seat to spending time with my family. I get frustrated at times because I do want to blog and work more, but I don't want to be away from my family and I'm jealous of every minute of my time. One thing my daughter has taught me is that every moment, no matter how simple or ordinary it is, can be filled with wonder and joy. And, I really want to appreciate these moments fully. Now.

So, I'm going to work towards spending a few moments each day to compose some ideas and put them into posts that show up more frequently here. To each of you who read this blog, thank you. I'll do my best to provide useful information (along with some personal thoughts, rants and fun) so that the moments you graciously take to stop by and read are well spent.

Mac|Life and Tom Kyte

I usually have my nose in my Kindle or iPad while traveling, but there's always the time between take-off and 10,000 feet where electronics are verboten where I need something to occupy my time. As my time filler, I will often pick up a magazine to read and on yesterday's trip home from the Hotsos Symposium in Dallas, I grabbed a Mac|Life magazine to read.

I l-o-v-e my Mac. My entire household is Mac - MacBook Pro, iMac, iPhone, iPad, iTouch, and a Nano...the works. So I get a kick out of picking up a Mac related publication to read and always find some cool stuff that I didn't know about lurking in the pages. This time however, I found something that I knew quite a lot about and it really tickled me when I saw it. At the back of the magazine they have a How-To article, and this month's article was on how to Read PDFs with iBooks. The thing that most caught my notice was the use of Tom Kyte's book "Expert Oracle Database Architecture" in the demo. Click on the supplied link to see the whole article, but here's a quick shot of what originally caught my eye in the magazine:

I loved it that Tom's book was the example book they chose to demo the how-to. What can I say? The geek in me had spasms when my Mac and Oracle lives crossed paths like that. Admittedly, if it had been one of the Oracle books I had co-authored that they had used, you'd have had to pull me off the ceiling, but Tom's book was still pretty spiffy.  :)

Another Hotsos Symposium in the books

Another Hotsos Symposium is in the books (well, the main Symposium is over with only the Training Day remaining tomorrow). As usual, it was a phenomenal event. Hotsos has got it down to a science on how to deliver a 5 Diamond event and it just seems to get better every year. My thanks go out to everyone at Hotsos who work so hard to make this event happen (special nod to Rhonda B and Becky G...sounds like a new girl band, huh?). It's a week chock full of the best technical information on Oracle performance you're going to find anywhere, a lot of great food, superb networking and "get-to-know" you time with other attendees, and (last, but not least) a fantastic themed party night to top it all off. This year's party theme was "Steampunk". The attire I donned for this photo is indicative of the genre if you're wondering what the heck Steampunk is (more photos here).

Thanks also to everyone who came to hear me speak. I delivered two presentations this year and had fun with both.

I hope everyone who attended had as good a time as I did and for those who missed it, there's always next year!

Hotsos Symposium

My favorite conference of the year is just around the corner.

The Hotsos Symposium will be held March 4-8 and will be celebrating its tenth anniversary. I'll be speaking again this year and, as always, am eagerly looking forward to the week. Every year the speakers, topics and opportunities for networking continue to excel and I'm sure this year will be no different. This year's Training Day event will be conducted by Jonathan Lewis so make sure to stay the extra day to take advantage of spending a day with him as he discusses "Designing Optimal SQL".

If you haven't signed up yet, there's still time. I'll look forward to seeing you there!

Bug update

We received notice of a patch to correct the bug I discussed with gathering stats on tables with virtual columns/function-based indexes in parallel in my previous post. The patch is number 10013177 and can be found at https://updates.oracle.com/download/10013177.html.

After applying the patch, all stats collections worked without error. Whew!

Bug alert!

While testing Oracle 11.2.0.2 (on Red Hat Enterprise Linux), I recently bumped up against a problem with stats collections using DEGREE > 1 that results in an ORA-600.

20:56:41 SQL> BEGIN DBMS_STATS.GATHER_TABLE_STATS('TR_OWNER','TR_POL', Estimate_Percent=>dbms_stats.AUTO_SAMPLE_SIZE, method_opt=>'FOR ALL INDEXED COLUMNS SIZE AUTO',cascade=>FALSE, Degree=>dbms_stats.AUTO_DEGREE); END;
20:56:41   2  /
BEGIN DBMS_STATS.GATHER_TABLE_STATS('TR_OWNER','TR_POL', Estimate_Percent=>dbms_stats.AUTO_SAMPLE_SIZE, method_opt=>'FOR ALL INDEXED COLUMNS SIZE AUTO',cascade=>FALSE, Degree=>dbms_stats.AUTO_DEGREE); END;
*
ERROR at line 1:
ORA-20011: Approximate NDV failed: ORA-12801: error signaled in parallel query
server P024, instance db100.srv.com:TRXTPLT2 (2)
ORA-00039: error during periodic action
ORA-00600: internal error code, arguments: [17114], [0x2AE3C33489B8], [], [],
[], [], [], [], [], [], [], []
ORA-06512: at "SYS.DBMS_STATS", line 23112
ORA-06512: at "SYS.DBMS_STATS", line 23205
ORA-06512: at line 1

If I execute with an estimate_percent of anything other than auto_sample_size, the ORA-20011 goes away, but the ORA-600 remains. Interestingly enough, if I execute with Degree=>1, everything is fine.

After doing more research and finding that I could execute a stats collection on other objects without any problems, I narrowed down the problem to the existence of certain types of function-based indexes. In particular, if the table has an index that uses either a DECODE or a CASE expression or a user-defined function, the problem occurs. As long as the table doesn't have one of these, everything works fine.

The contact to Oracle Support in regard to this issue replied as follows:

It possible you're getting the problem described in Bug:11774077 which is closed as a duplicate of Bug:10013177. For more information please read Note:10013177.8. Functional index causes max decode group by sql to truncate values / can cause dump.
Please check if one of the workarounds will solve your problem:
- Set _replace_virtual_columns=false
OR
- Set _disable_function_based_index=true
OR
- Gathering table stats using degree 1.

Ouch! Turning off the use of virtual columns and function-based indexes is *not* an option. We rely quite heavily on them in our application. And, for the tables that have this problem, gathering stats without doing it in parallel (degree 1) is doable, but not desirable as we have a limited window of time to collect stats and have relied on being able to collect in parallel to reduce the total time it takes to complete the collections.

We're still researching other options or workarounds and pushing on Oracle Support for a fix for this problem, but are not making much progress on either front at this point.

I'll update again soon with more information as I have it.