Blogs
Autonomous Transactions: a Poor Mis-Understood Feature
Submitted by Kevin Meade on Sun, 2007-09-09 12:48
In short an Autonomous Transaction lets a job, commit some data to the database as an ON-THE-SIDE event, without committing data in the MAIN-EVENT. Sounds useful and it can be. But the Autonomous Transaction can also be dangerous. An Autonomous Transaction is kind of like a teenage daughter (I have two) "Oh DAD! You just don't understand me". A lack of understanding is a foundation for trouble. Maybe we can’t understand our teenagers, but we can understand Autonomous Transactions a little better.
Partitioning in Oracle 11g
Submitted by venurani on Sun, 2007-09-02 22:59Partitioning is one of the most sought after options for data warehousing. Almost all Oracle data warehouses use partitioning to improve the performance of queries and also to ease the day-to-day maintenance complexities. Starting with 11G, more partitioning options have been provided and these should reduce the burden of the DBA to a great extent.
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Building a Dynamic Oracle ETL Procedure
Submitted by vjain on Tue, 2007-07-24 18:12
If you are on Oracle 9i or higher, you have external tables and pipelined table functions available to meet your ETL needs. But in order to utilize these tools in a dynamic ETL environment, you need to design PL/SQL procedures that can support the loading of files dynamically. This article will provide you with one design that has proven to be very robust and scalable.
Materialized View Fast Refreshes are Slow
Submitted by vjain on Fri, 2007-07-13 21:47
A materialized view that is verified to be fast refresh should update relatively fast. But, what happens when there are few changes to the master table, no network issues, no aggregation in the snapshot query and the refresh still runs slow?
Sizing your undo tablespace
Submitted by sethunathu on Thu, 2007-07-05 00:12
It is always a puzzle for a DBA to look into the user's complaint of getting "ORA-01555 Snapshot too old : rollback segment number x with name "_SYSSMUx$" too small " error. You have looked into the database. If your UNDO_MANAGEMENT is set to AUTO, you can not do anything to size the rollback segments manually since it is being managed by oracle. All the associated tables and indexes have been analyzed and statistics are up to date. The undo tabelspace is almost full. You may advise the user that there should be frequent commits (if it is a data loading process) or if there is a long running query and other users change the data that is being selected by the query, this can happen and in that case, if possible, advise the user not to run these two at the same time.
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Making Use of Table Functions -- Part II
Submitted by Art Trifonov on Mon, 2007-06-25 11:42
In Part I we discussed views, stored procedures, and table functions as the three options of returning record sets from the code stored in the database. In this section I will concentrate on table functions, demonstrating several kinds of solutions that utilize this feature.
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Making Use of Table Functions -- Part I
Submitted by Art Trifonov on Sun, 2007-06-24 12:01
Having in my practice found many useful applications for table functions I am a big fan of this feature. Unfortunately, I don’t think it always gets the attention it deserves. Oracle documentation does a decent job of explaining how to code table functions, but the use cases they provide can lead one to believe this feature has no universal application and is meant to solve just a few specific kinds of problems.
The SQL WITH Clause, (Order Your Thoughts, Reuse Your Code)
Submitted by Kevin Meade on Tue, 2007-06-19 14:59
So here I am writing even more documentation for my current Gig, and thinking once again, why not post it to OraFAQ and get double duty out of the document. So here is a discussion of the WITH clause that comes with the SELECT statement now. It is easy to use, and handy as all get out, but seems many people have not yet noticed it. Hmm... a SELECT statement that does not start with SELECT.
A Simple Example of Oracle Analytics: Running Totals
Submitted by Kevin Meade on Sun, 2007-06-17 19:40
Analytics are magic. But as with most software products; I seem to use only one percent of the features, ninety nine percent of the time. Indeed, having built warehouses and reporting systems for the last eighteen months, I look back and see that I got a lot done with only three Analytics, SUM, LAG, and LEAD. Knowing how intimidating Analytics can look to those who have not used them, I figured I’d show the uninitiated, how to get in through the back door, with a reduced look at the capability. You can do a lot with very little. We are going to discuss just one Analytic, SUM used to create running totals.
Installing the April 2007 Critical Patch Update on Windows
Submitted by Mohammad taj on Sat, 2007-06-16 07:56
This article describes the procedure to install the April 2007 CPU patch on Oracle Database Release 10.1.0.5. The Patch Number is p5907304_10105_WINNT.zip
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