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June 2015

Upgraded and can’t see the tables you could before ?

If you take a look at the "alter user" command in the old 9i documentation, you’ll see this:

DEFAULT ROLE Clause

Specify the roles granted by default to the user at logon. This clause can contain only roles that have been granted directly to the user with a GRANT statement. You cannot use the DEFAULT ROLE clause to enable:

  • Roles not granted to the user
  • Roles granted through other roles
  • Roles managed by an external service (such as the operating system), or by the Oracle Internet Directory

Oracle enables default roles at logon without requiring the user to specify their passwords.

Empty Leaf Blocks After Rollback Part II (Editions of You)

In my last post, I discussed how both 1/2 empty and totally empty leaf blocks can be generated by rolling back a bulk update operation. An important point I made within the comments of the previous post is that almost the exact scenario would have taken place had the transaction committed rather than rolled back. A […]

A First Technical Look At Hybrid Cloning in EM12c Release 5

The sales, support and technical teams were brought into the Denver Tech Center office to do some advanced training in Hybrid Cloud.  There were many take-aways from the days we spent in the office, (which is saying a lot-  most of you likely know how much I hate working anywhere but from home… :)) and I thought I would share a bit of this information with those th

Empty Leaf Blocks After Rollback Part I (Empty Spaces)

There’s been an interesting recent discussion on the OTN Database forum regarding “Index blank blocks after large update that was rolled back“. Setting aside the odd scenario of updating a column that previously had 20 million distinct values to the same value on a 2 billion row table, the key questions raised are why the blank index leaf blocks […]

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.

scott_CIHbrDpWIAA1-Cc

 

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”