Before you upgrade...what to expect (P6 Reporting Database)
By Jeffrey Mcdaniel-Oracle on Feb 24, 2014
If you are upgrading to P6 Reporting Database 3.1 or higher you'll want to allow for adequate time for the upgrade process. In this blog we will focus on upgrading the Star schema. The first major item to be aware of is that during the upgrade an ETL process is initiated. If you have a job scheduled to run your ETL process at a given time you'll want to make sure you allow enough time for the upgrade to finish or you may want to cancel the job until after the upgrade has completed. Having two ETL's running at the same time or overlapping at any point could be problematic for your STAR schema and the integrity of the data.
Generally running an upgrade will take longer than a traditional daily ETL. During the upgrade process a set of BCK (backup) tables are created. Backups are taken for all history (_history_f) and slowly changing dimension (_hd and _hf) tables. The schema is recreated and then the data is reinserted into the new tables. Also backed up is the ETL_CALCULATIONS table that contains the metadata calculations. After the backups are completed the ETL process is run to populate the remaining dimension and fact tables.
Before running an upgrade make sure to backup your STAR schema. You'll want to make sure this data, especially your history, is preserved incase of any kind of failure during the upgrade.