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March 2011

Exadata Database Machine: The Data Sheets Are Inaccurate! Part – I.

Yes, the title of this blog entry is a come-on. I am ever-so-slightly apologetic (smiley face).

This post follows the longest dry spell in my blogging over the last five years. I haven’t posted since early January and thus I am quite overdue for the next installment in my series regarding the Oracle Database 11g Direct NFS clonedb feature. I set out to make the next installment yesterday but before doing so I visited the analytics for my blog readership to see what’s been happening. I discovered that essentially nobody comes to this blog through Exadata related search terms anymore. That surprised me. Indeed, for the first—what—two or so years after Exadata went into general availability the first page worth of Google search results always included some of my posts. I can’t find any of my Exadata posts in the first several pages Google spoon-feeds me now when I google “Exadata.” This isn’t a wounded-soul post. I do have a point to make. Humor me for a moment while I show the top twenty search terms that have directed readers to my blog since January 1, 2011.

kevin closson 417
oracle performance 320
oracle 11g 290
oracle linux 200
oracle on flash SSD 188
oracle nfs clonedb 182
intel numa 133
oracle on nfs 122
oracle fibre channel 115
huge pages allocated 104
oracle orion 99
real application clusters 92
automatic memory management 82
oracle xeon 80
oracle i/o 78
oracle file systems 75
oracle numa 73
_enable_NUMA_support 73
greenplum versus exadata 70
oracle exadata 69

So, as far as search terms go there seems to be a lack of traffic coming to this site for Exadata-related information. The page views for my Exadata posts are high, but the search terms are lightly-weighted. This means folks generally read Exadata-related material here after being directed for a non-related search term. Oh well. I’d ordinarily say, “so what.” However, it is unbelievable to me how many people ask me questions each and every day that would be unnecessary if not for a quick read of one of the entries I posted before Oracle Open World 2010. That post, entitled Seven Fundamentals Everyone Should Know Before Attending Openworld 2010 Sessions might be better named You Really Need to Know This Little Bit About Exadata Before Anyone Else Tries to Tell You Anything About Exadata. Folks, if you get a moment and you care at all about Exadata, please do read that short blog entry. It will enhance your experience with your sales folks or any other such Exadata advocates. Indeed, who wants to be introduced to a technology solution by the folks trying to sell it to you. Now, don’t get me wrong. I’m not saying Exadata sales folks are prone to offering misinformation. What I’m trying to say is your interaction with sales folks will be enhanced if you don’t find yourself in such remedial space as the very definition of the product and its most basic fundamentals. That leads me to point out some of the folks who have taken the helm from me where  Exadata blog content is concerned.

Oaktable Network Members Booting Up Exadata Blogging

Fellow Oaktable Network member Kerry Osborne blogs about Exadata, in addition to his current efforts to write a book on the topic. I’ve seen the content of his book in my role as Technical Editor. I think you will all find it a must-read regarding Exadata because it is shaping up to be a very, very good book. I have the utmost of respect for fellow Oaktable Network members like Kerry. In addition to Kerry, Fritz Hoogland (a recent addition to the Oaktable Network) is also producing helpful Exadata-related content.  Oracle’s Uwe Hesse blogs frequently about Exadata-related matters as well. So, there, I’ve pointed out the places people graze for Exadata content these days. But I can’t stop there.

We Believe the Oracle Data Sheets
The content I’ve seen in blogs seems to mostly confirm the performance claims stated in Oracle Data Sheet materials. Let me put it another way. We all know the latest Exadata table/index scan rates (e.g., 25 GB/s HDD full rack or 70GB/s combined Flash + HDD).  We’ve seen the Data Sheets and we believe the cited throughput numbers. I have an idea—but first let me put on my sarcasm hat.  I’m going to predict that the next person to blog about Exadata will start out by blogging something very close to the following:

My big_favorite_table has many columns and a bazillion rows. On disk it requires 200 gigabytes of storage but with mirroring it takes up 400 gigabytes. When I run the following query—even without Exadata Smart Flash Cache—it only takes eight seconds on my full-rack Exadata configuration to get the result:

SQL> select count(*) from big_favorite_table where pk_number < 0;

Don’t get me wrong. It is important for folks to validate the Data Sheet numbers with their own personal testing. But folks, please, we believe the light-scan rates are what the marketing literature states.  I’m probably not alone in my desire to see blogs on users’ experience in solving particularly complex analytical data analysis problems involving vast amounts of data stored in Exadata. That sort of blogging is where social networking truly ads value—you know, going “beyond the Data Sheet.”

In Closing
So what does all this have to do with the infrequent nature of my blogging? Well, I’ll just have to leave that for a future entry. And, no, the Data Sheets on Exadata Database Machine are not inaccurate.

Filed under: oracle

I almost forgot

Just to annoy those who wonder why on earth I do this. I should point out (and keep pointing out) that

Disclosure: I'm attending this year's Hotsos Symposium with the help of the Oracle ACE Director program, which is paying my
travel and accommodation expenses. The time off work is at my own expense.

I am Number 4…

I get the feeling that I am Number 4 is trying to target prepubescent boys, the same way Twilight (how I hate that film) has captured the imagination of every young person with ovaries. The big difference is that prepubescent boys like to see things get shot and blown up. As a result, it’s much more palatable to an adult male than the tripe they keep serving up in the Twilight Saga. Gosh that film is bad…

I.a.N.4 has its fair share of teenage angst and everyone is Hollywood pretty, but it didn’t make me vomit and it didn’t have glittering vampires. How I hate glittering vampires…

So if you go in cold, I.a.N.4 is kinda meh. If you cleanse your palate first by watching any Twilight (what a completely awful set of movies) film, you will think I.a.N.4 is awesome and deserves a giant bag of Oscars.




or the Oracle support interface formerly known as Metalink.

In case you haven’t come across it, or if you’ve lost the URL, there is an HTML interface which, on the downside, doesn’t offer all the features but, on the upside, does seem to be a little more robust and a little faster. (I’ve added links to both the flash and html versions in my blogroll.)

Symposium 2011 - Day 0

It's a tough gig blogging from a conference, particularly this side of a presentation that I'm still (cough) polishing the slides for, but I can't bitch about Twitter decimating the blogging community without occasionally putting the slightest effort into redressing the balance.

After a long trip on Saturday (my solitary concession to Twitter - bitching about travel) I landed in the hotel bar and met the first of the many old friends I'm going to meet this week. Lest this seem like the opportunity for a name-dropping bonanza, I'm going to try to avoid specific names, but there were a variety of Marks there (if I include Marco) and Jacco, who was an unexpected surprise.

I've been upgraded to a suite and although it's a non-smoking one, I simply don't have the heart to ruin things for this lot by going ahead with the promised move.

They had a worse trip in the cargo hold, so it's the least I can do. (I can only imagine the reaction at the turn-down service when they'd carefully drawn the net curtains behind them! I can just imagine the little voices - "Behind us please, otherwise we can't see out ....")

Despite all my best efforts to ensure that this time, really, honestly I *will* have my slides done before the conference, I was there yesterday morning, polishing away and was really disappointed when my 2 hour afternoon nap turned into a 4 hour one finishing just in time for registration. I suppose I needed it, having had little sleep for days.

Walking around the hotel, registration and (yes) the bar, it occurred to me that of all the conferences I attend, this one feels most like a family outing. Again, that could be seen as a case of seeing the same old faces, my famous mates and so on, but in this case, I recognise about a third of the people milling around the hotel, attendees from past conferences and absolutely nothing to do with Oracle Corp, the Oak Table network or user group folk. This is just a bunch of people who (importantly) are all into the same stuff - Oracle performance-related - and come back year after year for more of the same. Add in the fact that we're all stuck in a single venue for presentations, meals, beers and all, it makes for a very intimate atmosphere conducive to informal conversations.

Those damn slides - I can not get them out of my mind and I won't be able to relax until about 11am tomorrow, when I'm done. I've simply bitten off more than I can chew and now that I'm at the 80 slide mark with more to be added, I have a couple of options

1) Drop some subjects and focus on a few properly.

2) Try to emulate Connor McDonald and talk my way convincingly and understandably through the slides at a rate of approximately 150 miles per hour. (If you've ever seen Connor present, you know how difficult that would be to emulate.)

I suspect I'll go for option 1 and, as I was saying to a few friends last night, I rarely go for the level of depth that will impress 3 people in the audience, but the level that will be of most value to most people.

Then, and this is outrageous but relevant name-dropping, just as I finished that very conversation, Tom Kyte walked up, said hello and pointed out that his closing presentation will be on things he's (re)-learned during the conference so that I'd better be able to teach him something new or something like that.

No pressure, then :-(

Damn, I hate the fact that I'm going to have to miss some things later to catch up but obviously I don't hate it enough or I wouldn't keep letting it happen.

Disclosure: I'm attending this year's Hotsos Symposium with the help
of the Oracle ACE Director program, which is paying my
travel and accommodation expenses. The time off work is at my own

Curiouser and Curiouser

It looks like England are going out of their way to make this World Cup interesting, but following them maddening. That ridiculously laboured effort in Nagpur followed by a stunning tie against one of the best two sides in the world before succumbing extremely poorly to the excellent Irish. Yesterday what do we get, a [...]


Just a quick note (because as a smartphone user this sort of thing bothers me a *lot*) to point out that today’s XKCD has an excellent example of how if you are going to anticipate your application’s client requests in some form of intelligent response, you really need to get it right so as not [...]

Public Appearances

Here is a short summary of my forthcoming public appearances:

  • 7th April: I'll be doing a one-day seminar in Switzerland on performance troubleshooting. This is loosely based on the Chapters 8 and 9 of the "Expert Oracle Practices" book that I have co-authored. If you want to get an idea of some of the details covered you can have a look at the material of my corresponding presentation. Of course the seminar will go much deeper than the presentation, since we'll spend a whole day on troubleshooting. This is being organized by Oracle University as part of their "Celebrity Seminar" program. You can find the details and booking options here.

Free ASH

If you’re running a version of Oracle older than 10g (where v$active_session_history appeared), or if you’re not using Enterprise Edition, or if you just don’t want to pay for the Diagnostic Pack licence, here are some links relating a free Java program that emulates the “Top Sessions” output of the Enterprise Manager screen:

Important Note:

If you want to query v$active_session_history (or any of the AWR objects) then you need to purchase the licence for the Diagnostic Pack). If you aren’t licensed you should only use the program in emulation mode.

Oracle Database Time Model Viewer in Excel 4

March 6, 2011 (Updated March 15, 2011) (Back to the Previous Post in the Series) (Forward to the Next Post in the Series) In the previous three parts of this series we started building an Oracle Database time model statistics viewer using nothing more than Microsoft Excel.  The end result will hopefully duplicate some of the functionality that [...]