Data warehouses, a multi-dimensional being (1) Tom Kyte [http://tkyte.blogspot.com/2005/05/any-plans-for-weekend.html]recently wrote on time travel. This got me thinking... time… the fourth dimension… dimensions… data warehouses. In the physical world around us we are used to thinking in three dimensions. A carpenter makes a box; it has
Partitions Yesterday I rambled on about tables, indexes and tablespaces. In passing I mentioned changes to partitioning schemes would be another posting.... so here it is. One of my customers operates a chain of outlets across the UK. Most outlets trade 7 days a week. In the original data warehouse sales
Data Warehousing Indexes & Tables & Tablespaces In a recent post David Aldridge [http://oraclesponge.blogspot.com/2005/05/inverting-myths.html] discusses an article on Oracle Myths that Mike Ault posted on searchoracle.com. One myth that got particular mention was the placing of tables and their indexes in separate tablespaces. Now David and I '
Data Warehousing Fresh views on refresh views So, you have got those MV in place and now need to keep them up to date, well there are three options: do-it-yourself, Complete refresh and 'Fast' refresh. To me, fast is not the right name, as under the covers all of the rows affected by
Data Warehousing Materialized views (revised.. but only a little!) In a recent blog reply Oracle Sponge Blog Squarepants [http://oraclesponge.blogspot.com/] (sorry David) mentioned not having much success with query rewrite on Materialized Views. Rashly I said I would blog something. These notes relate specifically to Oracle 9.2 in Data Warehouses. You will find changes with Oracle
Database performance One of the medium sized DWH I run is to have all the aggregate summaries rebuilt in few weeks time. The customer is replacing the old mainframe with a new ERP system, and at the same time restructuring their reporting structures and hence asked that we change all of the