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December 2011

Ad: The Oracle Query Optimizer 2-Day Seminar

The 31st of January and 1st of February 2012 I will present a 2-day seminar about the Oracle query optimizer in Ballerup (DK). The event is organized by Miracle A/S. The content, which is based on the chapters 2, 4, 5, 6, 9 and 10 of my book, is the following:

ASH Exploding Across Versions

 

I sometimes forget which versions of ASH have which fields, so here is a bit of a graphic and textual cheat sheet. (see https://sites.google.com/site/oraclemonitor/dba_hist_active_sess_history for some queries on ASH)

I Wish

A couple of days ago I wrote about some things I’d like to see in index statistics, which means changing dbms_stats.gather_index_stats(). Here’s an idea for dbms_stats.gather_table_stats(). I’d like to see the number of chained and migrated rows counted separately in dba_tables when we run the packaged procedure. The optimizer will use information about chained or migrated rows, but the information is only collected if you use the analyze command (and even then the two figures are summed into the single value chain_cnt) .

All Things Oracle

Last year I wrote a few articles for Simpletalk, a web service created by Redgate for users of SQL Server. This year, Redgate is setting up a similar service called “All things Oracle” (I’ve added a link in my blogroll) for Oracle users, and I’ve volunteered to write articles for them occasionally.

Some of the stuff they publish will be complete articles on their website, some will be short introductions with links to the authors’ own websites. My first article for them has just been posted – it’s an article that captures a couple of key points from the optimizer presentation I did at the UKOUG conference a couple of weeks ago.

Friday Philosophy – In Search of a Woodlouse

I don’t carry business cards around with me. I just never, ever think to get some done (either properly or with my trusty printer) and maybe this says something about my personal failings to sell myself. If anyone wants to contact me I tell them my email address and if they look confused I just say “ahh, Google me”. You see, having a very odd Surname means I am easy to find. {Reading this back I guess it could be interpreted as saying “I am so famous you will find me” but that is way, way, way from my meaning – I am going on the very unusual name that I have and nothing other than that!}

Oracle Nostalgia

When preparing the material for my “Oracle Lego – an introduction to Database Design” presentation for the UKOUG last week, I was looking back at my notes from a course on the topic from “a few years back”. There were a few bits which made me smile.

Oracle’s [SQL] implementation conforms to ANSI standard, although referential integrity will not be enforced until version 7

OUI Updates feature

One of the nice new features of the 11.2 installer for the Database (and indeed the installer for Enterprise Manager 12c) is the ability to tell the setup software to download any post release recommended updates for the product and to apply them at install time. The installer first of all prompts you for your [...]

Thanks Jonathan ...

... and Amit, of course!

I mentioned during my SPM presentation that Amit Poddar's excellent paper and presentation on One-Pass Distinct Sampling and Incremental Statistics had gone missing from the web, but Jonathan Lewis is now hosting the files on his original post about Amit's presentation.

UKOUG 2011 - My Presentations

Writing long blog posts about your own presentations is pretty narcisstic but it also allows me to rectify certain mistakes afterwards so, to make an existing private joke with friends public yet again (a theme that will be repeated later), I'll start off by saying I'm sorry.


What am I sorry about? Well, I broke one of the cardinal rules of presenting which I have berated others for in the past and promised myself (never mind anyone else) that I wouldn't do. In my first full-length presentation on Monday night I spent far too much time doing what I call 'Talking to my Mates'. There were so many asides to people I knew in the audience that it excluded other people who are listening and is a distraction from the point of the presentation. In all seriousness, I am sorry to anyone who was there who felt excluded as a result. Although there are no valid excuses, I can let you into a few of the reasons.

FBI trouble

In our application we extensively use a function-based index on an important table. Couple of days ago I’ve seen an interesting issue associated with this FBI, view and a GROUP BY query. I have to say I don’t have an explanation what exactly it is and how I should call it properly, hence just “trouble” in the subject line.