Not Exists

Another question on a seemingly simple “not exists” query has appeared on OTN just a few days after my last post about the construct. There are two little differences between the actual form of the two queries that make it worth repeating the analysis.

The first query was of the form:

select from big_table
where  not exists (select exact_matching_row from small table);

while the new query is of the form:

select from big_table alias1
where  (more...)


This one is quick and short. I have been asked few time, how can we check what value was specified to OSDBA, OSOPER and OSASM,especially during upgrades (to know what was it set to which initial installation)

# The DBA_GROUP is the OS group which is to be granted OSDBA privileges.
# The OPER_GROUP is the OS group which is to be granted OSOPER privileges.
# The OSASM_GROUP is the OS group which is to (more...)

Solaris 11 Zones & ZFS Sessions in Hyderabad

My last week's engagement on OU programs around Solaris 11 zones and Solaris 11 ZFS at Hyderabad concluded on Saturday. Thanks to each of the training delegates in the picture below for active participation and co-operation during the program.

Last but not least, heart felt gratitude to them for throwing a surprise advance birthday bash!

Docker – Take Two – Starting From Windows with Linux VM as Docker Host by Lucas Jellema

clip_image002My first attempt with Docker was from my Windows host machine using boot2docker, as described in this article: Boot2docker is a great tool for being able to work with Docker on a Windows machine. However, I ran into limitations – such as not being able to create containers with the GUI applications running in them. Besides, Linux seems to be – for now at least – the more natural environment for Docker. (more...)

Advanced Oracle Troubleshooting Guide – Part 12: control file parallel reads causing enq: SQ – contention waits?

Vishal Desai systematically troubleshooted an interesting case where the initial symptoms of the problem showed a spike of enq: SQ – contention waits, but he dug deeper – and found the root cause to be quite different. He followed the blockers of waiting sessions manually to reach the root cause – and also used my @ash/ash_wait_chains.sql and @ash/event_hist.sql scripts to extract the same information more conveniently (note that he had modified the scripts to (more...)

Database landscape 2014 visualization

I saw this database landscape 2014 overview from “451 Research” with an very nice visualization…

Oracle Midlands : Event #9

Oracle Midlands Event #9 is now confirmed with another great lineup!


Thanks to Red Stack Technology for sponsoring the event, allowing it to remain free!

Put the date in your diary. See you there!



Oracle Midlands : Event #9 was first posted on April 24, 2015 at 10:32 am.
©2012 "The ORACLE-BASE Blog". Use of this feed is for personal non-commercial use only. If you are not reading this article in your (more...)


Planning out my year, I decided to take the Oracle OCP and MySQL OCP exams. I checked for review books and was pleasantly surprised to find the soon to be released OCP MySQL Database Administrator Exam Guide (Exam 1Z0-883). However, I noticed that the book was actually prepared for the obsolete and discountinued Exams 1Z0-870, 1Z0-873, and 1Z0-874.

There isn’t an alternative review book for the OCP MySQL 5.6 Developer or Database Administrator (more...)

Golden Oldies

I’ve just been motivated to resurrect a couple of articles I wrote for DBAZine about 12 years ago on the topic of bitmap indexes. All three links point to Word 97 documents which I posted on my old website in September 2003. Despite their age they’re still surprisingly good.

Error deploying Oracle Composite with wrong encoding wsdl

We had some issues with deploying a composite which retrieves his wsdl for the partnerlinks from Nexus.
The supplier of the services adds the archive with the wsdl artifacts in Nexus, we download the dependency and after that we compile/validate the composite against the downloaded set of artifacts.

For one particular partnerlink the composite just wouldn’t compile.

Error message :

Validating composite "c:ReposcompositesmydomainobjectMyServicecomposite.xml"
c:ReposcompositesmydomainobjectMyServicecomposite.xml:21: error: Load of wsdl "oramds:/apps/xsd/nextgen/gm/services/mydomainobject/2/myservice.wsdl" failed
c:ReposcompositesmydomainobjectMyServicecomposite.xml:44:  (more...)

#C15LV Collaborate’15 updates!!

Hi All, Last week, I registered my presence at Collaborate’15 in Las Vegas as a speaker, attendee and at Oracle demo booth duty. It was an awesome experience meeting some polished brains and smart minds. After the first day of registration, I attended the #DBIM12c session by Maria Colgan, #DB12c Multitenant by John McHugh and #Exadata session … Continue reading

Oracle and Docker

So, as many of you know, I've been working out different ways to host my Oracle labs and demos instances without chewing up phenomenal amounts of disk space and processing power.  Lately, I've been diving into Docker.

Docker has turned out to be pretty cool and very easy to learn.  And it's lightweight.  The idea is that you run containers - your app, your operating system, and your virtual machine - bundled together in a (more...)

Silent Upgrade Oracle GoldenGate to

Today I worked on silent upgrade of Oracle GoldenGate from to, so thought to blog it which might help some of you. These are the steps I performed

Current GoldenGate Home –> /oracle/app/product/ogg12.1.2

1. Gather the details of GoldenGate Processes before stopping them

GGSCI> STOP  (more...)


From time to time I read a question (or, worse, an answer) on OTN and wonder how someone could have managed to misunderstand some fundamental feature of Oracle – and then, as I keep telling people everyone should do – I re-read the manuals and realise that that sometimes the manuals make it really easy to come to the wrong conclusion.

Having nothing exciting to do on the plane to Bucharest today, I decided it (more...)

Oracle Enterprise Manager EMCLI on Mac OS X

EMCLI is not certified or supported on Mac OS X, but I wondered if it is possible to run on my new macbook. I searched metalink, googled and couldn’t found any useful information. I thought it should be easy because EMCLI is a java application certified to run almost all enterprise operating systems including HP-UX, AIX, Linux, Windows, Solaris, and we all remember “write once, run everywhere” slogan of Java. Unfortunately it wasn’t as easy (more...)

Oracle Cleanup a Schema

Back in January 2014, I wrote a script to cleanup an Oracle student schema. It worked well until I started using APEX 4 in my student schema. You create the following 75 objects when you create an APEX 4 schema.

------------ -------
TABLE		  17
INDEX		  28
LOB		   9

Here’s the modified script that ignores the objects created automatically by Oracle APEX when you create a student (more...)

Real Push Button Refresh with Raspberry Pi

Push Button

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...)

ASM Rebalance Too Slow? 3 Tips To Improve Rebalance Times


I’ve run into a few customers recently who have had problems with their ASM rebalance operations running too slowly. Surprisingly, there were some simple concepts being overlooked – and once these were understood, the rebalance times were dramatically improved. For that reason, I’m documenting the solutions here… I hope that somebody, somewhere benefits…

1. Don’t Overbalance

Every time you run an ALTER DISKGROUP <NAME> REBALANCE operation you initiate a large amount of I/O workload as (more...)

Goldengate Data Manipulation – When Inserts & Updates differ

One very useful aspect of Golden Gate is to allow the manipulation of data between the source and the destinations.

One recent problem that I encountered was to alter the data differently for inserts than for updates. This was caused by the receiving system needing to have some default data in columns which may or may not be supplied by the insert or update statements. This is slightly more complex than first imagined:

UKOUG Tech15 : Call For Papers

I just noticed Neil Chandler‘s blog post about the Call For Papers for UKOUG Tech15.


I’ve just submitted my sessions for this year. It’s in my home town, so life will be easy this year. :)



UKOUG Tech15 : Call For Papers was first posted on April 16, 2015 at 3:20 pm.
©2012 "The ORACLE-BASE Blog". Use of this feed is for personal non-commercial use only. If you are not reading (more...)