A new beginning

It has been long since my last post and the time has come to resume my postings and refresh my blog. A lot of things happened last few months, I’ve been really busy working on many different projects, graduate university and the very big step – relocate to London with (more...)

Missing IPV6 address for local network interfaces causes service timeout

Year ago I installed Weblogic server + Oralce database server for a customer. Few months later my colleagues asked me whether something has changed in the environment or if something happened at the data center, because they started to see Java exceptions for unknown hostname for a web service they were calling and this was happening only from time to time. We’ve checked the firewall rules, DNS and all the stuff, but everything seemed to be working fine. The only solution by that time they came out was to add the hostname to the hosts file of the Weblogic server. (more...)

How to run standalone Oracle APEX Listener 2.0 with Oracle 11g XE and APEX 4.1.1

This is short guide on how to run standalone Oracle APEX Listener 2.0 beta with Oracle 11g XE. I’m using Oracle Enterprise Linux 5.7 for running Oracle APEX Listener and Oracle Database 11g XE with APEX 4.1.1. Although running APEX Listener standalone is not supported I’m using it to run several internal applications for company needs.

When using APEX Listener with Oracle XE, APEX won’t work properly and white screen appears when APEX is open. This is because the APEX images are stored in the XML DB repository, but APEX Listener have to be run with (more...)

How I run Oracle VM 2.2 guests with custom network configuration

Recently I was given three virtual machines running Oracle Enterprise Linux 5 and Oracle 11gR2 RAC on Oracle VM 2.2.1, copied straight from /OVS/running_pool/. I had to get these machines up and running at my lab environment, but I found hard to setup the network. I’ve spent half day in debugging without success, but finally found a workaround, which I’ll explain here.

Just a little technical notes – Oracle VM (xen) has three main setup configurations within /etc/xen/xend-config.sxp:

Bridge Networking – this configuration is configured by default and it’s simplest to configure. Using this type of networking (more...)

Failed creating physical standby database

These days I’m implementing Oracle Dataguard for two Oracle databases 10.2 as part of disaster recovery project, one of them is around 1.7TB, not yet production. As part of the DG setup backups have to be available for both primary and standby. I preferred to use ASM and was able to negotiate with the storage admin to run storage replication for the FRA disks during the backup. This way I would have the same structure and files, locally at the disaster site immediately after the backup of the primary database is completed.

Unfortunately two weeks passed and by (more...)

Oracle Database 10.2 datapump job fails because of invalid queue

Recently I had to clone one schema from Oracle Database on HP-UX to on Linux. The first problem came when I tried to export it and got the following errors:

UDE-00008: operation generated ORACLE error 31623
ORA-31623: a job is not attached to this session via the specified handle
ORA-06512: at "SYS.DBMS_DATAPUMP", line 2315
ORA-06512: at "SYS.DBMS_DATAPUMP", line 3185
ORA-06512: at line 1


These gave me no sign of what could be the problem, but when I tried to export only the metadata I got ORA-00600 which helped me (more...)

Oracle 11g XE listener does not start when there is another database running

If for any reason you have a two databases running on the same server and one of them is Oracle 11g Express Edition then you will get surprised that listener of XE is not started automatically during boot if there is another listener already running. Debugging the startup script I found that this happens because of a bug in the code, which assumes that XE listener is running if it finds the word LISTENER within the processes list.

In file /etc/init.d/oracle-xe, at line 556 the code is failing:

+ status='oracle 2889 1 0 May13 ? 00:00:05 /oracle/ora112se/bin/tnslsnr LISTENER -inherit'
+  (more...)

Not able to update Web service process in APEX 4.1

Last month I created a simple APEX application with enabled mobile support and latest version of jQuery, which integrates with HP Service Manager through web services. The purpose was to give option for company engineers to open and update incidents through mobile in few easy steps.

The first step was to create form and report by using the web service. At this point web service request process is created where authentication and input parameter are described. The problem appears if you try to change any parameter and update the web service process. This is the error:

 Error error updating web  (more...)

Automatically backup Oracle APEX applications to Subversion

In continue of my previous posts about APEX and Subversion I made a short script using APEXExport utility to automate and backup APEX to Subversion repository.

I’m using Oracle Express Edition 11.2, which by default doesn’t have the APEXExport utility. That’s why you need first to create the directory holding it and then copy the utility there.


Create destination directory holding the utility and copy APEXExport.class there:

mkdir -p $ORACLE_HOME/utilities/oracle/apex


Create backup directory in the SVN project for holding the backup files:

[oracle@dbsrv ~]$ svn mkdir -m "Making a backup dir."