RDBMS Server

Oracle RDBMS Server Articles

How to avoid primary key collision on multiple sites?


This article provides several comparative methods to avoid primary key conflicts across multiple sites.

cbruhn2's picture

Enabling plan_sql from statspack



When you setup statspack with level 6 you can have information on the sql_plan associated with a sql.

Understanding Indexes


Of iPods and Indexes

I'm not really an "early-adopter" of technology. Don't get me wrong; I love it, I just don't want to feed the addiction. When I do get a new piece of technology though, it's like a fever; I can't concentrate on anything until I've read the manual from cover to cover and found out everything it can do, every built-in gizmo, and every trashy piece of after-market merchandise that can be plugged into it.

Yet another alert log puzzle


A handy alert log is invaluable for troubleshooting database problems. A RAC database has multiple alert logs.
I prefer to monitor them through a single table.

"A master failing to make an entry in the vessel's official
logbook as required by this part is liable to the Government for a
civil penalty of $200.

United States Code. Title 46 - Shipping. Subtitle II -Vessels and seamen, Part G - Merchant seamen protection and relief. Chapter 1113 -Official logbooks.

How meticulously do you keep your book log, Captain?
Luckily for us, our databases are as much ships as they are first mates. They are intelligent enough to keep their own records. And those logs are as important as vessel logs of the past, because the information carried by an early 21st century database could be easily worth more than 1450 tons of tea carried by Cutty Sark in 1870 en route from Shanghai to London.

As Oracle does all the mundane work, our role becomes more creative - to inspect and properly use the gathered information.

cbruhn2's picture

Experimenting with the continous mining


Today I have been experimenting with the new feature of continous mining with logmnr.

My setup

  • Oracle Database 10g Enterprise Edition Release - Production With the Partitioning, OLAP and Data Mining options
  • ALTER DATABASE ADD SUPPLEMENTAL LOG DATA or we don't see the funny things in the redologfiles
I now starts the logminer session in one window with :
dbms_Logmnr.Start_Logmnr(StartTime => SYSDATE - 1 / 24, Options => dbms_Logmnr.dict_From_OnLine_Catalog + dbms_Logmnr.Continuous_Mine);

FROM v$Logmnr_Logs;

cbruhn2's picture

Strange behavior from resetlogs.


During a test of some backup setup with rman I ran into problem running the restore / recover command.

Natalka Roshak's picture

Securing Your Database: A simple Brute Force Blocker


If you've had to change a Unix password, you know that most systems won't let you use just anything as a password - your password must be a minimum length, and must not be too easy to guess or brute-force. Oracle doesn't come with this capability installed out of the box, but Oracle 8 and above let DBAs define a custom function to complexity-check user passwords. Oracle provides a default password verification function to do some basic checking, although DBAs need to know about it and install it manually.

Natalka Roshak's picture

Using Oracle's recycle bin


One of the many new features that Oracle 10g introduced is the recyclebin. When enabled, this feature works a little bit like the familiar Windows recycle bin or Mac Trash. Dropped tables go "into" the recyclebin, and can be restored from the recyclebin. OraFAQ has already published an article covering the basics; in this article, I'll cover some of the more subtle aspects of the recyclebin.

Logical vs Physical Standby database


Logical vs. Physical Standby databases
Submitted By Rama Subramoniam

A Quick Primer

Standby databases, in a nutshell, acts as a failover for our mission critical production databases. When production database crashes, applications can quickly switchover to the stand by databases.

Oracle provides two types of standby databases:

1. Physical Standby Database

Standby database is called “physical” if the physical structure of stand by exactly matches with stand by structure. Archived redo log transferred from primary database will be directly applied to the stand by database.

Removing duplicate indexes


Indexes are used to speed up data access by SQL statements, but there is no free lunch as each additional index increases:

  • The time needed to perform DML (Insert/Update/Delete) operation on the table (because additional index entries must be updated).
  • The enqueue time (during DML the corresponding index entries are locked decreasing the ability of parallel updates and causing transactions, issued by another session(s) to wait.
  • The generated UNDO volume.
  • The disk space needed to store the index information.


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