June 2015

Friday Philosophy – At What Point Can You Claim a Skill?

I’ve just installed Oracle 12C on my laptop {I know, why only now?}. I went for the option to have a Container database with a pluggable database within it. {It is easy and free to install Oracle on your own home machine – so long as it is for personal use only and you are singed up to OTN (which is also free) }.

12C with pluggable databases (PDBs) is a little different to the last few versions of Oracle as it introduces this whole concept of the Container database that holds portions of the data dictionary and, within that, what we used to think of as Oracle instances plugged in underneath it. It is not *quite* like that – but this post is not about the technical aspects of Oracle 12C multitentant databases. And you will see why.

Unique Oracle Security Trainings In York, England, September 2015

I have just updated all of our Oracle Security training offerings on our company website. I have revamped all class pages and added two page pdf flyers for each of our four training classes. In have also updated the list....[Read More]

Posted by Pete On 25/06/15 At 04:36 PM

Oracle Midlands : Event #10

Just a quick heads-up about the next Oracle Midlands event. It’s good to encourage new speakers, so Mike is giving this new, unknown kid a shot at the limelight. I hope you will all come along to show your support.

om10

Cheers

Tim…

Quiz Time. Why Do Deletes Cause An Index To Grow ? (Up The Hill Backwards)

OK, time for a little quiz. One of the things I’ve seen at a number of sites is the almost fanatical drive to make indexes as small as possible because indexes that are larger than necessary both waste storage and hurt performance. Or so the theory goes …   :) In many cases, this drives DBAs to […]

Why do people show Azure so much love?

cloudThe title of this post is taken from tweet I saw a few weeks ago and it keeps coming back to haunt me, so I thought I would comment on it.

Let me start by saying I don’t have any context as to why the tweeter thought people were showing Azure so much love. From my perspective, I kind-of like Azure and I think it is what my employer will end up using, but I’m not a crazed fan-boy about it. :)

Good new SQL tuning book

People ask me from time to time what are some good SQL tuning books. It’s a tough question to answer. There are some seminal books such as “SQL Tuning” by Dan Tow and “Cost Based Optimizer Fundamentals” by Jonathan Lewis, but these are advanced books  that few I know have actually read from cover to cover. If you are looking for practical SQL tuning cookbooks you might want something a little less advanced.  For a practical approach, I love “Refactoring SQL Applications” by #111111;"> Stephane Faroult which is an easy read, again, it’s not a straight forward SQL tuning book.

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 […]