I was recently reminded of the chaos that can be caused by an unindexed foreign key column when there are corresponding updates or deletes from the parent table. To illustrate this particular situation here is some example DDL
CREATE TABLE parent_t
(
parent_id INTEGER NOT NULL,
parent_name VARCHAR2(30) NULL,
CONSTRAINT parent_t_pk PRIMARY KEY (parent_id)
);

INSERT INTO parent_t SELECT object_id, object_name FROM [...]

Resizing datafiles is something that I seem to do a lot of.  Usually, I am increasing them to allow for data growth but sometimes I need to shrink them to reclaim unused space.  When shrinking a datafile, you cannot make it smaller than the highest allocated extent in the datafile, aka the High Water Mark [...]

Happy Valentines Day!
Many DBAs are aware that the Automatic Workload Repository (AWR) including Active Session History (ASH) is only available to users licensed for Enterprise Edition with the Diagnostic Pack.  This is invaluable data for conducting performance tuning based on recent historical data but off limits unless you are properly licensed.  Those 10g users who [...]

For those of you who did not attend yesterday’s (November 9th, 2011) NOCOUG (Northern California Oracle User Group - http://nocoug.org) meeting, you missed a good one!  Here’s a quick recap of what I saw interesting to me:
The keynote by Feurstein Coding Therapy for Database Professionals actually had some good food for thought. Some of [...]

Introduction

I have mentioned before that the best way to insure Oracle RDBMS uptime, is to create and maintain a physical standby database. There simply is no more reliable way to insure uptime for the Oracle RDBMS.
Creating a standby database involves these steps:

Creating a standby controlfile from the primary database & transferring it to [...]

Sooner or later, every DBA will need to address how to manage storage capacity in their databases. Nearly every database needs more storage as time goes on, and without attention, the database will fill up, and new data/inserts can’t happen. It’s been my experience that bad space mangement is the root cause of a high [...]

As Oracle consultants we often get caught up in the esoteric areas of performance, such as contention, complex execution plans, and obscure parameters.  But we forget that sometimes it’s the little things that count, many of which we learned in the DBA101 phase of our careers.
I was reminded of this recently at one of our [...]