Execution Plan Instability – What is the problem?
The Oracle Optimizer is a complex piece of software and with every release it becomes more complex.
In the beginning, the Optimizer was rule-based.
The Optimizer had a ranked list of heuristics used to optimize a query, picking the lowest ranked rule available.
This rule-based mode, whilst still in use with some internal Oracle dictionary queries, has been unsupported since version 10.1.
This means that (more...)
In this post, we’re going to perform a push button refresh of an Oracle Database, Application Express (APEX) installation, and Tomcat webserver.
“But Oracle Alchemist,” you’re probably thinking, “we know about that. You’ve told us about how Delphix can provision and refresh data.” And yes, you’d be right. But I wasn’t done yet.
We’re going to perform a refresh of an Oracle Database, APEX installation, and Tomcat running in Amazon Web Services, replicated from (more...)
Just a small Sunday night anecdote with a wider point. I, or maybe a colleague, recently received an update statement from a developer. Now, this developer is long of tooth and is well versed in the ways of Oracle data manipulation.
The aforementioned update statement contained an interesting hint. BYPASS_UJVC. You may not have heard of this hint. It’s not commonly used, although it’s been around since Oracle 8.1.5. Mainly because it is (more...)
Sequences on Oracle databases are simple, but there are some basic truths about sequences which need to be understood if you are going to use them, especially on RAC:
- Sequences will have “holes” in them, even if you specify NOCACHE (e.g. if you rollback your transaction).
- Don’t specify NOCACHE. It doesn’t scale.
- Sequences will NOT necessarily be, erm, sequential for your transactions. That will depend upon the COMMIT order and if you are (more...)
(blogarhythm ~ Diablo - Don't Fret)
The Fretboard is a pretty simple Arduino project that visualizes the build status of up to 24 projects with an addressable LED array. The latest incarnation of the project is housed in an old classical guitar … hence the name ;-)
All the code and design details for The Fretboard are open-source and available at fretboard.tardate.com
. Feel free to fork or borrow any ideas for your (more...)
Seamless cloning of an application stack is an outstanding goal. Seamless cloning of an application stack including the full production database, application server, and webserver in a few minutes with next to zero disk space used or configuration required is the best goal since Alexander Graham Bell decided he wanted a better way tell Mr. Watson to “come here.”
So in the spirit of discovery, I’ve installed Oracle REST Data Services (ORDS) 2.0 (more...)
Sometimes development is just work
No matter how cool your job is, no matter how many people are looking at you or your company for best practises, sometimes developing software is just work On this blog I’ve shared examples of companies that people nowadays see as successful, like Netflix, Twitter, Spotify, or the online retailer bol.com.
To prove my point I’ve checked the release notes of Netflix and Spotify apps. Here (more...)
I have Tom Kyte’s “Ask Tom” in my feed reader, and every now and then it opens for questions and the flood pours in. Quite often there is an interesting question, but more often than not there are quite a lot of “poor” questions: some just poorly worded, some too-easily-googleable, others are could-have-answered-from-the-docs questions. It’s not dissimilar to StackOverflow, which doesn’t suffer so much because of the army of people who work together to either improve or (more...)
Last week I attended Oracle OpenWorld 2014, and it was an outstanding event filled with great people, awesome sessions, and a few outstanding notable experiences.
Personally I thought the messaging behind the conference itself wasn’t as amazing and upbeat as OpenWorld 2013, but that’s almost to be expected. Last year there was a ton of buzz around the introduction of Oracle 12c, Big Data was a buzzword that people were totally excited (more...)
Are you going to Oracle OpenWorld 2014? I am, and I hope to see you there! As you probably know, OpenWorld is a humongous event with tens of thousands of people in attendance and some amazing presentations. Why, I even hear Oracle’s new CTO might be there. I wonder if he has anything to talk about?
This year we’ll have a ton of activity at the Delphix booth. You can check out the speaking schedule, (more...)
Some days before ZeroTurnaround has released XRebel , a new tool to recognized problems in your web applications, when you make your developer test.
This was promising, so I give it a short try for Oracle ADF applications. For this blog I use the Summit ADF application, delivered by Oracle, but I have tried with our own application too. Test is done in JDeveloper 12.1.2.
After the download there are some easy steps (more...)
If you speak german and you are interested in quality assurance for your ADF projects you should come and attend my presentation at DOAG Development on 06/04/2014 in Dusseldorf.
I will show you, how you can implement in the JDeveloper IDE and in Continous Integration server Jenkins:
- static code analysis with PMD, FindBugs and Checkstyle
- Commit tests with JUnit, Mockito and Powermock for Mockito
- Code coverage for commit tests with JaCoCo
- Acceptance tests with JUnit (more...)
Back in March of last year I wrote an article on the five frequently misused metrics in Oracle: These Aren’t the Metrics You’re Looking For.
To sum up, my five picks for the most misused metrics were:
- db file scattered read – Scattered reads aren’t always full table scans, and they’re certainly not always bad.
- Parse to Execute Ratio – This is not a metric that shows how often you’re hard parsing, no matter how (more...)
Random thoughts on a Friday afternoon…
We’ve all got problems. More to the point, every IT department or team has problems of some kind. It’s why we hire consultants, buy products, start long and arduous journeys into the great unknown depths of root cause analysis, and so on.
What fascinates me is the level at which we come to identify with our problems. When I’ve gone into an environment to deliver recommendations, the conversation usually (more...)
Alchemists are best known for their (completely fictional and entirely ridiculous, but that’s besides the point) amazing ability to turn lead into gold. Let’s face it, there’s a lot of lead in the Oracle world. Bugs, angry developers, metrics that can seem to elude human understanding…but I (more...)
Funny thing I had today. Well funny, not when you want to make progress in your work, but still interesting what I discovered when I tried to isolate the problem…I found a way to make the same mistake and have Oracle return three different errors, dependent on the order of (more...)
Thank you all who attended my sessions at NYOUG Fall Conference this morning. I appreciate spending you most precious commodity - your time
- with me. I sincerely hope you found both the presentations enlightening as well as entertaining.
Please see the details of the sessions below along with the (more...)
Not too sure what I changed on my laptop, possibly just installation of another product or perhaps Microsoft or similar updates, but when I went to edit a BI Publisher RTF template I got the following error message on clicking ANY button in the BI Publisher plugin for Microsoft Word.
Matrix : What you must learn is that these rules are no different than rules of a computer system. Some of them can be bent, others can be broken. Understand?
Usually an unique index grants the uniqueness of all rows in a specific table which have non-null values; But (more...)
The New Zealand Oracle Users Group - NZOUG Conference 2013
is open for registrations
and Earlybird pricing is still available! The agenda
is now available.
NZOUG 2013 is being held in Wellington at the iconic Te Papa Museum
on the beautiful waterfront on the 18th and 19th of March, with an additional Workshop Day
on the 20th March.
The conference will see a wealth of brilliant speakers
from around the world, including Tom Kyte, Graham Wood, Andrew Holdsworth, John Schiff and Nadia Bendjedou and of course top speakers from Middle Earth
(NZ) as well. Tom, Andrew and Graham will be (more...)