If you are wondering what I am busy with then this post explains it.

As you may noticed I am still testing one of the Oracle systems using the SLOB framework and learning on my way. I ran several tests with the same parameters (Readers 24) and I noticed that for one reason or another awr.txt reports different runtimes: Read the rest of this entry . . .

dbm_configurator.xls is needed to generate databasemachine.xml file which is needed by OEM 12c to discover an exadata cluster.

Following is a step  by step process as how to generate databasemachine.xml file to be used with OEM 12c:

Read the rest of this entry . . .

I have a confession to make: I hate webinars. I find it difficult to concentrate on a disembodies voice. I typically get distracted and find myself checking email and blogs even during the best webinars. Watching a webinar is a bit like watching DVD of a live show – not as fun as live show, and not as polished as a music video.

But one can’t escape the fact that webinars are quickly becoming a very popular learning method. The best presenters I know are giving webinars and every DBA uses them to improve his knowledge. I’m happy to report that despite the fact that I sat alone in a room and talked to my cat about ODA performance for a full hour the presentation went rather well.

If you are interested in the topic but missed the webinar or if you want to hear it again, you can view our recording.

I also uploaded the slides to slideshare, so you can take a better look at our benchmark results and study our consolidation methods at your own pace. Unfortunately, Slideshare mangled few of the slides, so if they look unclear you can use the recorded webinar to disambiguate.

There were few questions I did not have time to address during the webinar. Interestingly enough, many of them have nothing to do with ODA but are rather about my benchmarking methods.
Read the rest of this entry . . .

I was recently puzzled by the question, “Which query will be faster?”:

SELECT * FROM table WHERE pk = x OR pk = x1 OR pk = x2 ...

Or

SELECT * FROM table WHERE pk IN (x1, x2,...);

There are 50k values in both IN and OR clauses and lookup is done via primary key. Sounds simple. My first reaction was: “No, there is no difference between these two queries.” I checked execution plan and it showed range scan of primary key for both IN and OR queries. Execution plans were identical and I also did a quick search on the web, but didn’t find any clear description on whether there are any differences in how MySQL handles these types of queries. So my final answer was: “No, there is no difference”.
Read the rest of this entry . . .

At $work we have a need for a little job daemon that would poll jobs and process them. If there was only one kind of job involved, the solution could be nothing more complicated than

while ( my @jobs = poll_jobs() ) {
    process( $_ ) for @jobs;
    sleep $a_wee_bit;
}

But there are more than one type of job, so the solution that we need will have to be a little more complex. In fact, that’s something that typically can be dealt with with event-drived programs. As I don’t dabble often with that kind of stuff, I jumped on the occasion to play around a little bit. Perl doesn’t lack in event-based systems, POE and AnyEvent are two big names there, but I decided to have fun with Reflex, a Moose-based system built on top of POE.

To get to my goal, I decided that I would have a generic Poller class. For each type of job to monitor and run, I will create a different object with parameters to tell it how often to poll, how to poll and what to do with the stuff it poll. Sounds good? Perfect, then let’s go.

Read the rest of this entry . . .

It is evident and beyond doubt now that the new media technologies like Twitter and Facebook are not going to wipe-out the blogs, rather they are complimenting each other very nicely and it seems they were made for each other. This Log Buffer Edition enhances this match, and presents you Log Buffer #272.

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After completing your Oracle VM and Oracle VM Manager installation (see my previous blog posts here) you are ready to start your friendship with Oracle VM technology. However to make your life and experience even more enjoyable I would suggest you to follow a few simple steps listed bellow.

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These days, to craft basic emails, I go with Email::Simple. For the more heavy stuff with attachements and what-nots, I reach out for Email::MIME. Together, they make a pretty awesome duo. But… (come on, admit it, you knew there was going to be a ‘but’)

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For the third consecutive year, NoCOUG is hosting an international SQL challenge. Last year we ran into a small difficulty where the international DBA community proved too clever and solved the challenge before we could properly publicize it.

A good DBA learns from her mistakes, and this year we are pre-announcing the challenge:
The challenge will be revealed on Monday, May 21 at 9 AM PST at http://bit.ly/JvJS46.

Bookmark the location and check the challenge at 9am, or risk being late to the party. And speaking of parties…

In this challenge, the Wicked Witch of the West needs help in creating a magic spell to ensure that the Third Annual Witching & Wizarding Ball is a grand success.

The winner will receive the August Order of the Wooden Pretzel in keeping with the Steven Feuerstein’s observation that “some people can perform seeming miracles with straight SQL, but the statements end up looking like pretzels created by somebody who is experimenting with hallucinogens.”

There are currently four knights of the August Order of the Wooden Pretzel: Alberto Dell’Era (Italy) who won the first challenge in 2009 and Andre Araujo (Australia), Rob van Wijk (Netherlands), and Ilya Chuhnakov (Russia) who won the second challenge in 2011.

In recognition that SQL is not the only language in which enterprising developers can create pretzels on hallucinogens, the challenge is also open to NoSQL solutions. In which case we will want to see creative use of non-relational data models. The inclusion of NoSQL can also be attributed to the fact that one of the judges is a big fan of NoSQL databases. I’m a very un-biased judge, btw, and can only be bribed with the finest scotch.

May the quickest, most entertaining, most educational, most creative and somewhat readable solution prevail!

This is just a quick post to share my first 3.1.1 Oracle VM Manager (OVMM) troubleshooting experience.

After the initial installation I rebooted the server, tried to access OVMM https://ovmmhost:7002/ovm/console and received the following error in a browser screen:

Unexpected error during login (com.oracle.ovm.mgr.api.exception.FailedOperationException: OVMAPI_6000E Internal Error: Connection refused Connection refused[[ < date > ), please consult logs for details. OVMAPI_6000E Internal Error: Connection refused Connection refused
< date >
Unexpected error during login (com.oracle.ovm.mgr.api.exception.FailedOperationException: OVMAPI_6000E Internal Error: Connection refused Connection refused[[ < date > ), please consult logs for details. OVMAPI_6000E Internal Error: Connection refused Connection refused date .

Read the rest of this entry . . .