In the last two months, I had the pleasure to speak at four different conferences. Each of them was unique in its own way, and all of them were definitely worth to attend. Of course, it is not possible to write down all impressions in one blog post, but at least I try to write a short personal review of these four events.
New features are one reason to upgrade to a new Oracle release, bug fixes of known bugs are another one. With Oracle 19c, at least two bugs related to Automatic List Partitioning were fixed. I did some tests with Auto-List Partitioning on an Oracle 19.3 database.
Oracle 19c provides a set of new SQL functions for bitmap operations. They allow fast computation of COUNT(DISTINCT) expressions. What is the purpose of these functions? The Oracle documentation is very sparse, but at least it tells us that the main focus are Materialized Views on aggregated data. Let’s have a detailed look at this new feature.
Today, it is exactly twenty years ago since I started my job as a consultant for Trivadis. In 1999, I never thought that I will stay in one company for such a long time. A retrospective of the last two decades.
Materialized Views are often used in data warehouses to improve query performance on aggregated data. But what if it takes too long to refresh the materialized views? Here are some basic rules to improve refresh performance.
The data type of primary key and foreign key columns has an impact on the query performance. This should be considered in the design decision of keys in a Data Vault schema.
Oracle Autonomous Data Warehouse Cloud does not allow to create indexes. Is this a problem for star schemas because no Star Transformation can be used? Or are the required bitmap indexes automatically created? A look under the hood of ADWC.