Analytic functions in real life

Yesterday while working on a real production report I found a requirement that forced me to come up with a bit nontrivial usage of analytic functions. Here is the problem (translated to SCOTT-level terms):

- I have a table that contains a DATE column (HIREDATE)
- Input parameter is also a date (IN_DT)
- For each department I need to show all rows that have HIREDATE after IN_DT plus the most recent row from the (more...)

Unusual Deadlock

Prompted by a question on OTN I came up with a strategy for producing an ORA-00060 deadlock that DIDN’T produce a deadlock graph (because there isn’t one) and didn’t get reported in the alert log (at least, not when tested on 11.2.0.4). It’s a situation that shouldn’t arise in a production system because it’s doing the sorts of things that you shouldn’t do in a production system: but possibly if you’re trying (more...)

What happened at the first ORCLAPEX-BE Meetup?

Yesterday I attended the first ORCLAPEX-BE Meetup. Very well organised by Dimitri and Roeland. Remarkable fact: I was not the only "foreigner" as around 30 - 40% of the - around 16 - attendees where Dutch! So Meetups can even easily cross borders ...




So after some initial socialising.... 
... ... Roeland explained the concept of these kind of meetups.






In the next hour Dimitri went over all the great new features of APEX5, like Page Designer, (more...)

Oracle Database 12.1.0.2.0 – Getting started with JSON Path Expressions

Yesterday my colleague Alex and I had the pleasure to do some extra presentations during AMIS’s Oracle OpenWorld preview evening. While still not getting around...

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COUNT_DISTINCT für postgres

Thomas Vondra erläutert in seinem Blog die selbst gebaute Funktion COUNT_DISTINCT, mit deren Hilfe sich COUNT(DISTINCT column) Operationen beschleunigen lassen, da sie auf eine (inhaltlich unnötige) Sortierung der Ergebnisse verzichtet. Ursprünglich verwendete er bei seiner Implementierung eine Hash Table, die inzwischen aber durch ein einfaches Array mit sortierten und unsortierten Elementen ersetzt wurde. Interessant finde ich dabei einerseits die großartigen Möglichkeiten der Erweiterbarkeit des postgres-Funktionsumfangs und andererseits die Tatsache, dass hier offenbar ein ähnlicher Lösungsweg (more...)

Vorteile des Zugriffs auf den In-Memory column store.

Maria Colgan erläutert im Rahmen ihrer Serie zur In-Memory-Option in Oracle 12.1.0.2 die spezifischen Vorteile, die ein TABLE ACCESS IN MEMORY FULL mit sich bringt:
  • der Zugriff beschränkt sich auf die relevanten Spalten - was bei der klassischen Zeilen-orientierten Speicherung natürlich nicht möglich wäre.
  • die IM-Daten liegen in komprimierter Form vor, weil sie beim Laden in den Speicher komprimiert werden.
  • unnötige Daten werden beim Lesen ausgeschlossen, was durch In-Memory Storage Indexes sichergestellt (more...)

Retro Day – Workload Management in WebLogic Server

Quite recently, I stumbled across this older but still very relevant whitepaper on the workload management capabilities of  WebLogic Server.  Written by one of the key engineers at the time, who later went on to become an architectect, it explains the workings of the new work load management feature introduced into WebLogic Server at the time and covers the concepts of work-manager configuration and effect, work scheduling and prioritization, overload protection and  more.

This (more...)

Full Disclosure

Over the next few weeks, I'll be sharing plenty of information relating to Oracle OpenWorld.  Mostly on this blog or via my Twitter account (@fteter).  As always, I try to share information in an accurate and a positive way.  I'm an Oracle fan, but I always try to balance that with accuracy and honesty.  In that spirit, it's important for me to make some disclosures about my attendance at OOW14.

I'm attending on "The King's (more...)

Oracle Priority Support Infogram for 11-SEP-2014


OpenWorld

From Appsconsultants.comsome good general pointers for attendees: This year’s OpenWorld expect 70000 attendees, 10 tips to maximize your conference experience.

From Chris Warticki's Blog - Oracle Support: All Access Pass to Oracle Support.

Pythian is one of our favorite companies here at the Infogram. Here’s their rundown on their Oracle OpenWorld presence.

WebCenter customers, don’t miss this announcement from the Oracle WebCenter blog: Oracle WebCenter & Oracle BPM Customer Appreciation Reception.

Virtual Circuit Wait

On Monday we had some performance problems on a system that includes a database which uses shared servers.  The top wait was “virtual circuit wait”.  Here are the top 5 events for a 52 minute time frame:

Top 5 Timed Foreground Events

Event Waits Time(s) Avg wait (ms) % DB time Wait Class
virtual circuit wait 1,388,199 17,917 13 50.98 Network
db file sequential read 1,186,933 9,252 8 26.33 User I/O
(more...)

How to See When Your Database Was Opened

This was tested on Oracle 11.2: 

SQL> l
  1* select startup_time from v$instance
SQL> /
 
STARTUP_TIME
------------
24-MAY-12
 
SQL>


Rittman Mead/Oracle Data Integration Speakeasy @ Oracle Open World

If you are attending Oracle Open World this year and fancy bit of a different experience, come and join Rittman Mead and Oracle’s Data Integration teams for drinks and networking at 7pm on Tuesday 30th September at the Local Edition speakeasy on Market Street.

We will be providing a couple of hours of free drinks with the opportunity to quiz our leading data integration experts and Oracle’s data integration team about any aspect of the (more...)

CPU-starved LGWR

In my recent post I showed how log file sync (LFS) and log file parallel write (LFPW) look for normal systems. I think it would also be interesting to compare that to the situation when LGWR does not have enough CPU.

I happen to have collected LGWR and database-level trace files for a 11.2.0.3 database on a Solaris 10 server which was under serious pressure (50 threads mostly inserting and committing data, only 32 (more...)

apropos("^ore")

We have all been in the position of trying to find the name of a command in a language, particularly if you are not totally sure of the full command name.

I've been working with R a lot recently and in particular Oracle R Enterprise. I was always trying to remember what the full command name was. Then I found the apropos function. The apropos function allows you to search R for commands based on (more...)

Grid logging in 12.1.0.2

Most of the talk about Oracle’s release of 12.1.0.2 is about the InMemory feature, but more things have changed, for example some essential things about loggin in the Grid Infrastructure have changed. Normally in Oracle Grid Infrastructure logging for Grid components was done in $GI_HOME:

oracle@dm01db01(*gridinfra):/home/oracle> cd $ORACLE_HOME/log/`hostname -s`/
oracle@dm01db01(*gridinfra):/u01/app/12.1.0.2/grid/log/dm01db01>

There we have the main alert log for GI and several subdirectories for the GI binaries where they write (more...)

API Management in WildFly 8.1 with Overlord

I gave a brief introduction about the Overlord project family yesterday. Today it's time to test-drive a bit. The API Management sub-project released a 1.0.0.Alpha1 two days ago and introduces the first set of features according to the 18-Month roadmap.

What is APIMan exactly?
It is an API management system which can either be embedded with existing frameworks or applications or even run as a separate system. So far, so good. But (more...)

APEX 5.0: Bye bye Tabs, welcome to Navigation Lists

In previous versions of Oracle APEX (< 5.0) you could use Tabs for the navigation in your application.


Tabs were not that flexible, they were typical on top of your page in a specific look and feel. Since APEX 4.x I started to dismiss using Tabs in most of the cases, instead I would use a List with the "Page Tabs" template if people wanted that look and feel.

APEX 5.0 introduces (more...)

Can you have high redundancy files in a normal redundancy diskgroup?

One of the perks of teaching classes is that I get to research questions asked. In the last Exadata Administration Class I taught someone asked: can you have your disk groups in Exadata on normal redundancy yet have certain databases use high redundancy? This would be a good interview question …

The answer is yes, which I remembered from researching material on the 11g RAC book but I wanted to prove that it is the (more...)

IOUG Oracle EM SIG Techcast on Oracle Enterprise Manager 12c

I have got an opportunity to present Webinar/TECHCAST arranged by IOUG EM SIG for IOUG Oracle EM SIG Techcast: Oracle Enterprise Manager 12c – How to Achieve Heights of Success. The webcast was presented Wednesday, September 10, at 12 noon CDT. Recording to be posted this week! Click here to be taken to the Special [...]

NOFILENAMECHECK Parameter Causes DUPLICATE DATABASE To Ignore DB_CREATE_FILE_DEST?

Last week I was creating a new testing database from a backup of our demo database, both under Oracle 11.2.0.3. I grabbed one of my old scripts to handle the duplicate function, which looked similar to this:

connect auxiliary /;
run {

        duplicate database to testdb
                backup location '$BACKUPDIR'
                nofilenamecheck;

}

One important difference between the demo database and this new test database is that the original demo database (more...)