For Developers: Making Friends with the Oracle Database - presentation by Cary Millsap

Here is a link to a Cary Millsap presentation -- a must read for developers who interact with Oracle Databases. This article can save you some time and heartache!

From the Abstract:

Is Intermedia in use?

When copying or moving databases it is nice to know if features are used or not. Sure you can always query DBA_REGISTRY to see what has been set up on the source databases, but is it always necessary to install everything that shows up in DBA_REGISTRY on your target systems? Intermedia is a feature that can be a particular pain to install and configure.

Generating lots of DDL with DBMS_METADATA...

After using many different tools to generate DDL I usually end up back at DBMS_METADATA. DBMS_METADATA is an Oracle supplied package that became available with Oracle 9. DBMS_METADATA is an API that can be used to generate the DDL of most any object in an Oracle database. It is most handy for getting Table or Index DDL but there is a complete list of objects that DBMS_METADATA handles here.

Table Example

Make your queries Self Aware...

In past Oracle versions you may have used USERENV() to access some of this information. The information is now available in the 'USERENV' namespace of the sys_context function. Here is a useful example. When monitoring the current in-flight SQL it is nice to exclude the current query from the results:

Using PL/SQL region in Oracle Application Express

I'm still an Application Express beginner -- I'm used to web development that is closer to the HTML. While I am getting used to Apex's Regions and Templates sometimes you just need to build some HTML on your own. I have found some Apex helper functions that can help you whip up an anonymous PL/SQL block that can generate this. In Apex, add a "PL/SQL" region. You will get a blank textbox where you can enter some PL/SQL code. If you have the Demo application installed you can try this out:

Manage rebuilding of indexes...

I've been doing some speed testing of rebuilding indexes. I have been adding the PARALLEL clause to my alter index ... rebuild; statements but it has been suggested to me to also run multiple indexes rebuilds in parallel. So if I am wanting to run 4 rebuilds in parallel I could try to make 4 .SQL scripts with the appropriate commands. But what if one finishes early? Then I will be left with only 3 running. Here is a solution: 1) Create a table to hold the list of indexes you want to rebuild:
create table rebuild_indexes (

HammerOra Quick Start...

Its time to test some IO.

I have used OraBM/OraStress in the past to throw a load at an Oracle server.

This time I wanted to see what else was out there. I had seen mention of HammerOra on forums and listserves so I figured I'de give it a shot. Here's what it took to get it running on a Windows server.

1) Download and Install HammerOra

Their home page is here:

I can't login! The server is down!

Yup. I'm tired of hearing this from users. Since I changed jobs from a software development house to a more focused DBA role I hear this a lot. As much as I'de like to just log into their app server and comb through logs to find the problem like the old days... I have to debug what I can from the server side and get the app server folks looking from their end. Here is a quickie script that should work on most Unices.

Manage other user's jobs with DBMS_IJOB...

I had a user that called me about jobs not running on a 9i database. I logged in and found a complete mess. Broken jobs, some DBMS_JOB calls would hang, jobs existed for users that no longer existed (I didn't even know that was possible!). Because things were such a mess I just wanted to remove all the jobs and start from scratch. But I needed to drop jobs for a user that no longer existed. Using DBMS_JOB even SYS does not have complete control of jobs. How can I remove a job for a user that no longer exists? Enter DBMS_IJOB.

More stupid RMAN tricks: ORA-01843 From RMAN

So I've got a backup script that runs a BACKUP DATABASE followed by a BACKUP ARCHIVELOG command. The BACKUP ARCHIVELOG FROM TIME command runs to collect all the archived logs created since the beginning of the Level 0.


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