If you’ve been unfortunate enough to follow my dithering on Twitter recently you’ll know that I’ve been lurching between thinking that there is and isn’t a problem with Oracle’s tracking of I/O statistics in its AWR reports.
I’m now convinced there is a problem, but I can’t work out what causes it… so step 1 is to describe the problem here, after which step 2 will probably be to sit back and hope someone far (more...)
I’ve posted a new installation cookbook for using Oracle within a virtual machine running on Oracle VM. Surprisingly, I was unable to come up with a satisfactory method of accessing external storage that did not involve the use of Oracle ASMLib…
Oracle Linux 6 Update 5 within an Oracle VM Template
Filed under: Blog
, oracle vm
The default value of METHOD_OPT from 10g onwards is ‘FOR ALL COLUMNS SIZE AUTO’.
The definition of AUTO as per Oracle documentation is :
AUTO: Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
This basically implies that Oracle will automatically create histograms on those columns which have skewed data distribution and there are SQL statements referencing those columns.
However, this gives rise to (more...)
This post is about memory management on the operating system level of an Oracle database. The first question that might pop in your head is: isn’t this a solved problem? The answer is: yes, if you use Oracle’s AMM (Automatic Memory Management) feature, which let’s you set a limit for the Oracle datababase’s two main memory area’s: SGA and PGA. But in my opinion any serious, real life, usage of an Oracle database on Linux (more...)
When you happen to have a customer that want’s to use Data Guard on Oracle RAC without a license for Active Data Guard then you might want to read this post.
You probably have searched on the internet (just like I did) and already found this nice post from Uwe: http://uhesse.com/2013/10/01/parameter-to-prevent-license-violation-with-active-data-guard/
If you haven’t already then go ahead and read it, but come back when you also use RAC.
I had set-up Data Guard between (more...)
Learning, relearning or unforgetting…
What value is there in a DISABLEd constraint?
This was a question on the OTN forums this week and a) my first reply was wrong and b) I couldn’t find a clear demonstration elsewhere.
The documentation is clear.
The ETL process commonly verifies that certain constraints are true. For example, it can validate all of the foreign keys in the data coming into the fact table. This means that (more...)
I was recently contacted by a customer who runs a busy ERP system on their Oracle database. Their users have been screaming for some time about unpredictable performance, where application screens which would usually open in under a second suddenly take an age. ERP systems are legendary for this, of course, because as each screen loads the application tends to fire off a glut of queries to populate all the various fields, graphs and so (more...)
Recently, I’ve been engaged in a conversation on the OTN community pages about upgrading Oracle GoldenGate 12c from 22.214.171.124.0 to the 126.96.36.199.0. During the discussion I mentioned that you can upgrade using the Oracle Universal Installer (OUI) that is now available with Oracle GoldenGate 12c. The upgrade process I’m going to show you here is an in-place upgrade of Oracle GoldenGate 12c for Oracle Database 12c.
Recently I came across the situation where I knew for a fact that my sessions to the database where dead because I pulled the power plug out of my application server for a failover test. But the sessions stayed visible in the database and kept their locks therefor the failover failed.
Now how is that possible?
First let me sketch the layout of the setup.
Suppose you have a vendor supplied application that runs on their middleware. That (more...)
Security is always a big deal. In setting up Oracle GoldenGate the capture (extract) and apply (replicat) parameter files need to be configured to log in to the database which they will perform operations. In order to do this the Oracle GoldenGate User name and password need to be provided in the parameter files. Example 1 shows how the database login is traditionally done in a extract or replicat parameter file.
A couple of weeks ago I wrote a post about my trip to Oracle OpenWorld 2014 and the surprise announcement of the Oracle FS1 Flash Array. I posted it on the Violin Memory corporate website here:
Follow the link to find out whether I thought it was the most amazing product in the history of storage, or simply a rehashed Pillar Axiom hybrid array with some SSDs and a ton of marketing. (more...)
Just a quick note to point out that the October PSU was just released. The database has a few more vulnerabilities than usual (31), but they are mostly related to Java and the high CVSS score of 9 only applies to people running Oracle on windows. (On other operating systems, the highest score is 6.5.)
I did happen to glance at the announcement on the security blog, and I thought this short (more...)
The following steps are what I did for installing 188.8.131.52 on Windows.
1. Download the Oracle installation ZIP files from the Oracle Downloads page.
2. Unzip the two 12c downloads files into the same directory.
3. Go to the newly created directory (it is probably called 'database') and you will find a file called setup.exe. Double click on this file.
After a couple of seconds you will see the Oracle Database (more...)
This is another guest post from my buddy Nate Fuzi, who performs the same role as me for Violin but is based in the US instead of EMEA. Because he’s an American, Nate believes that “football” is played using your hands and that the ball is actually egg-shaped. This is of course ridiculous, because as the entire rest of the world knows, this is football whereas the game Nate is thinking of is (more...)
A couple of people have asked me recently about a classic problem that most DBAs know: how to view ASM trace files in the VIM editor when the filenames start with a + character. To my surprise, there are actually quite a few different ways of doing it. Since it’s come up, I thought I’d list a few of them here… If you have another one to add, feel free to comment. I know that (more...)
OTech Magazine – Summer 2014
The fourth issue of OTech Magazine, the independent magazine for Oracle professionals, is available. For the summer 2014 issue there are some more personal articles included. Titles vary from The Spiritual Programmer to The Next Generation: Oracle SOA Suite 12c and back via How to protect your sensitive data using Oracle Data Vault.
Download OTech Magazine – Summer 2014 here.