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June 2015

You never stop learning

My mate Scott Wesley, whose specialty is Apex, is currently at Kscope having the time of his life (well, I hope so Smile).  He tweeted this picture last night of his conference badge, mainly about the “I love Apex” buttons, but something else struck me.

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12c Parallel Execution New Features: 1 SLAVE distribution

When certain SQL features get used in pre-12c versions that force non-parallel evaluation, like using ROWNUM or certain Analytic Functions like LAG/LEAD, then - depending on the overall plan shape - Oracle can start to decompose the parallel execution plan into several so called DFO trees (If you want learn more about DFO trees and DFOs I recommend watching my online tutorial on my Youtube channel).Now having multiple DFO trees in a single parallel execution plan comes with several side effects that are confusing and complicate matters unnecessarily, like each DFO tree allocates its own PX slave set(s), and so each one can potenially end up with a different DOP, which means you can have more than one DOP in a single parallel execution plan.Depending on the overall plan shape this might also mean that a DFO tree can get started multiple t

Upcoming Conference Sessions

I’m glad to be home after a couple weeks in Europe, speaking at both the Harmony 15 conference in beautiful Tallinn, Estonia and then as a keynote speaker at AOUG in lovely Vienna, Austria the week after.  I get to pretty much stay close to home for the next two months, traveling only a bit, but I want to go over the upcoming conferences that I’ll be speaking at the next couple months.

Return from The Temple of Apple

I doubt many of you are on tenterhooks as to how I got on with my phone today {after my << rant last Friday}. But I’m going to tell you anyway.

Overall, Apple have gone some way to redeeming themselves.

I got myself down into Cambridge this morning to visit the Apple Store, at my allotted slot of 10:10 {I later witnessed someone attempting to be 15 minutes early for their slot – and they were asked to go and have a coffee and come back. The customer was unimpressed as they had lugged some huge Apple monitor in with them}.

Index Tree Dumps in Oracle 12c Database (New Age)

I’ve previously discussed Index Tree Dumps but I’ve recently found a nice little improvement that’s been introduced in Oracle Database 12c. Let’s begin by creating a little table and index: To generate an Index Tree Dump, we first need the OBJECT_ID of the index: And then use it to generate the Index Tree Dump: Previously, an […]

Open Source is Free – Free like a puppy!

I’m at the ODTUG Kscope conference in Hollywood Florida and was just talking with some Oracle folks about Open Source (yes, Oracle has people devoted to working with Open Source tools) and I shared with them my general comments to students and colleagues about Open Source.

There are two kinds of free:

1. Here’s a free cup of coffee (or beer or soda…)

2. Here’s a free puppy

When accepting option 1 (free coffee) you take it, consume it, and enjoy.

When accepting option 2 (free puppy) you take it, you find a place for it to sleep, you take it to the vet, you walk the puppy, you feed the puppy, and oh-yeah — every once in a while the puppy might make a mess on your floor! You’ve made a commitment.
(I cannot take credit for the metaphor; I first heard it used by friend and colleague Jim Cody of Cardinal Directions – thanks Jim!)

Clearly, “free” is not always “completely free”

Performance #datachat

 

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photo by #212124;" title="Go to Tom Woodward's photostream" href="https://www.flickr.com/photos/bionicteaching/" data-track="attributionNameClick" data-rapid_p="51">Tom Woodward

 Summary of responses to questions from Solarwinds #datachat back in the fall.

[Oracle] DB Optimizer Part XII - Revealing SQL Plan Directive details for existing/loaded cursor from CBO (and SQL Dynamic Sampling Services) trace

Introduction

The idea for this blog post is based on a recent Twitter discussion with Martin Berger, Martin Bach and Mauro Pagano about revealing SQL Plan Directive details for an existing cursor as walking through the standard Oracle data dictionary views can be very time consuming/slow and there are still some details missing about the dynamic sampling task itself, even if you have found what you are looking for.

 

Friday Philosophy – Friday Afternoon Phone

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Update on my trip to the Apple Store >>}

There used to be a phrase in the car industry in the UK (I don’t know about elsewhere) a “Friday Afternoon Car“. This is a car which is unusually unreliable, as it was built on Friday afternoon when the workers were tired, the weekend was coming and, heck, they might have been to the pub at lunch. It is occasionally used just to describe something that is a bit crap and unreliable.

Old ventures and new adventures

I have some news, two items actually.

First, today (it’s still 18th June in California) is my blog’s 8th anniversary!

I wrote my first blog post, about Advanced Oracle Troubleshooting, exactly 8 years ago, on 18th June 2007 and have written 229 blog posts since. I had started writing and accumulating my TPT script collection a couple of years earlier and now it has over 1000 files in it! And no, I don’t remember what all of them do and even why I had written them. Also I haven’t yet created an index/documentation for all of them (maybe on the 10th anniversary? ;)

Thanks everyone for your support, reading, commenting and the ideas we’ve exchanged over all these years, it’s been awesome to learn something new every single day!