Oracle Database Undo space explained

In this blog post I will talk about the basic workings of Automatic Undo Management, which can cause ORA-01555 and ORA-30036 issues.

The scope is Automatic Undo Management used in 10g and 11g, but has to be explicitly set for 9i (UNDO_MANAGEMENT = AUTO). Manual Undo Management is out of scope for this blog.

The Undo tablespace is a normal tablespace like any other, but only Oracle is controlling what is happening inside it.

Undo something

The Undo tablespace is used for several features: ROLLBACK, READ CONSISTENCY and FLASHBACK technology. Continue reading

Access to HTTPS via utl_http using the orapki wallet command

This HTTPS via utl_http using orapki recipe is prepared with certificates and the orapki tool having some sweet and spicy taste. You may also use the Oracle Wallet manager instead of using orapki but for Oracle RDBMS you will need to have Enterprise Edition and Advanced Security pack licenses. Continue reading

Install Oracle Instant Client / ODAC

Installing the Oracle Instant Client will save you ~600 megabyes compared to the ‘full’ Oracle Client.

Installation steps:

  1. Read some basic info here…
  2. Download Basic Package for Oracle site
  3. Unzip to directory x (your ORACLE_HOME)
  4. Set PATH (Windows) or LD_LIBRARY_PATH (*nix) to the Instant Client directory x
  5. Move TNSNAMES.ora to directory x/network/admin (or set TNS_ADMIN and ORACLE_HOME).
  6. Extend with SQL*Plus Package from (optional)
  7. Start your application

Read my full article here: Whiteblog – Installing the Oracle Instant Client. (links in referred blog might not work!)

ODAC

OLE DB, .NET and ASP.NET drivers are not included in the instant client (first Oracle link might suggest it is). These are included in the ODAC package, download them separately at these locations:

Instant Client vs Full Client (Administrator and Runtime)

What Are The Different Oracle Client Components Installed With Different Installation Type In (too much to sum up):

Client mater note

Master Note For Oracle Database Client Installation (Doc ID 1157463.1)

Happy consulting!

Checked for relevance on 7 March 2016.

Oracle Database 11g Release 2 for Windows released!

They have finally arrived, the Windows 64 and 32 bit versions of Oracle 11gR2.

Download Oracle Database 11g Release 2 for Windows

The 64 bit version was released a bit earlier, so I was hoping the 32 bit version would not come… Why do we want the 32 bit versions? Older systems? Ancient systems! Why…?!

Now I don’t have an excuse to update my almost 10 years old Windows XP OS (running on 64bit hardware) to a much nicer Windows 7 64 bit. The only excuse now is that I could use 600+ megs of memory… enough to run that XP OS virtually!

A small demo machine with SOA/BPEL/WebLogic/ADF/APEX

Today I had to babysit a demo machine I set-up for a proof of concept. All went well, as I expected.

A two gigabyte RAM Linux machine with SOA/BPEL 11g, two WebLogic 10.3 domains extended with ADF and Apex XE running on it. It kept running, but at one point is had only 30 megs of memory left!

Check out ‘Extending your WebLogic standalone environment with ADF runtime libraries‘ for more information about setting up the WebLogic environment with ADF.

Temporary stop listener to log with ‘set log_status’

When moving/deleting the listener.log, I used to stop and start the listener and move/delete the listener in between the actions.
This method has a big inconvenience: users can not connect to the database for a few seconds…
What I never knew was that the listener could be told to stop and start logging and take the appropriate action in between. Continue reading

Multiple Oracle homes on Windows, which one is used?

When having multiple Oracle homes on Windows, how is decided which Oracle home (in the registry) is used by an Oracle binary? Which NLS_LANG or TNS_ADMIN setting from the registry is used?

The answer is binary, path, oracle.key, registry… and which for Windows. Continue reading