Although Query Rewrite on Materialized Views is a powerful feature which is available in Oracle databases for a long time, it is rarely used. Many developers and database administrators don’t know about it or do not use it because they think it is too complex. In this blog post, I try to reduce the concerns about complexity with some general design tips for Query Rewrite.
If you work with Data Vault for a data warehouse running in an Oracle database, I strongly recommend to use Oracle 12.2 or higher. Why that? Since Oracle 12c Release 2, join elimination works for more than one join column. This is essential for queries on a Data Vault schema.
In the last four weeks, I had the chance to speak at three different conferences. This was the finish of an intensive conference year for me with many impressions, learning, knowledge sharing, new and old contacts and of course a lot of fun.
NLS (National Language Support) parameters are very useful for multilingual applications in an Oracle database. But it is important to understand their impact on query performance. I was aware that NLS is important for indexes, but never thought about its impact on partitioning.
September was my second round of conferences this year. A presented my session “Avoid Horror Queries: Keep Your SQL Simple and Fast” on three different conferences, two of them organized by Trivadis.
An almost unknown simplification in the usage of dbms_xplan is possible since Oracle 12.2. Sometimes, there are small details that makes our job (a little bit) easier.
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.