At the end of my last MySQL post I mentioned strange behavior with GROUP BY and DISTINCT. This MySQL “feature” could save some resources on sorts and aggregates but generally I would avoid it as this is not portable solution. Generally speaking, query output is non-deterministic — it depends on the full table scan implementation and on the physical order of rows in a table. This means that it’s actually a bug and , instead, MySQL should produce and error on those statements.
I’ve started to use DBCA more and I try to use its template management capabilities. It looks like templates is not the most robust feature of Database Configuration Assistant. Sometimes, there are issues when I want to reuse template. I reviewed the parameters and found that control_files is set to an empty string. Checked Metaclick and, indeed, this error is related to empty control_files parameter.
This article will discuss how to make many-to-many relationships in data warehousing easily queried by novice SQL users using point-and-click query tools.
Those of you that that enjoyed my post on Stability, Agility, Scalability and Cost: The eBay example are sure to like this technical interview of the desperate efforts to stay only a bit behind the traffic demands at MySpace, written by David Carr at Baseline Magazine. A worthy read for those of you interested in the lofty heights of database scaling, where we pack oxygen and have to make some choices and compromises along the way.
Welcome to the 28th edition of Log Buffer, the weekly review of database blogs. It was a busy week in the blogs, but then, it always is.
For several years, I worked as an Oracle Consulting employee, and I’d like to share my experience in that role, working on a massive Oracle Applications implementation deployed in an FDA-regulated company.
If you have found rman backups slow in Oracle 10.2.0.2, you should check out note 375386.1 on metalink. It seems the CBO isn’t all its made out to be, and you have to force rman to use the RULE hint instead to make your rman backup run faster
Not that I participate there often but couple months ago I pulled out my 7 years old account there and wanted to change its password. To my surprise – I’m not able to do it.
In one of my previous posts I mentioned SYSTEM_PRIVILEGE_MAP view. Taking this thread further, I looked into another nice view – V$ENABLEDPRIVS – showing the privileges enabled for the session at the moment. It should be pretty useful if you decide to add some diagnostics into your application. You might also find it very helpful to call from PL/SQL.
We humans are not able to process large amount of precise data. In any human–readable report, we don’t need more than ten or twenty lines of numbers. Every time we look at processes or data more complex that that, we employ simplifications — graph trends, mind–mapping, aggregations, and so on. How will we make computers process information just as humans do? Perhaps we can find the answer inside ourselves if we figure out how our minds work. We recognize images even though our brain is not capable of processing huge amounts of data in milliseconds.