Sunday, June 21st, 2009 by Peter Scott
One of the things I sometimes come across when looking at legacy ETL code for data loading is the misuse of query hints to “improve” data load performance. Sometimes DBAs or developers do not remember that “tuning the select” may not be the same thing as “tuning the insert”; Jonathan Lewis wrote about an example […]
Thursday, June 11th, 2009 by Stewart Bryson
If you follow the blog, then you know that Mark recently posted about materialized views for aggregation, located here.
One of the issues he encountered was how to refresh materialized views based on tables loaded with partition exchanges… a common approach to loading fact tables while minimizing the downtime for the reporting schema. Once the […]
Tuesday, May 26th, 2009 by Peter Scott
One of my pet hates is the inappropriate use of dynamic SQL within ETL processes, for example building a command as VARCHAR2 string then using it in an “execute immediate” statement. Putting commands into strings whether hard-coded ones within the package or procedure, retrieved from some ‘code’ table in the database or even built on-the-fly […]
Wednesday, April 22nd, 2009 by Stewart Bryson
As a quick introduction, I’m Stewart Bryson, Technical Director for North America. It seems strange to be posting an entry on this blog after so many years of reading it, and learning from it. The momentum it has in the community is something I do not take lightly, so hopefully, this post and others from […]
Saturday, April 18th, 2009 by Mark Rittman
Materialized Views and Partitioning are two key Oracle features when working with data warehouses. Using them together though can sometimes cause unexpected problems when you need to refresh them, as we found on a recent project. Here’s what happened, reproduced using the SH Sample Schema.
Our initial requirement was thus: the client had a fact table […]
