One of the most spectacular new facilities in Release 2 of the Oracle 11g Database is called Edition Based Redefinition – not a name perhaps that suggests any spectacle. EBR (Edition Based Redefinition) is a mechanism that allows on line application upgrade with no planned downtime. In short, the new release is built up in parallel to the existing one, in the same schema and using the same database objects; only the new (modified) objects live in another dimension and do not impact the existing objects. Once the entire set of new and changed objects has been created and recompiled, the database administrator can start routing new sessions to the new release; existing sessions can continue to run against the original set of objects – and new sessions if so desired can also run against the orginal set.
A set of object versions – mutually consistent and interdependent – which in software engineering terms would be duped a release or stripe and in Oracle Software Configuration Manager (Designer) terms a configuration is called an edition in 11gR2 lingo. An Edition is a combination of new objects, new versions of objects and inherited pre-existing versions that together make up a meaningful set that forms the state of the database for a longer or shorter period of time. Releases of applications will typically target a specific Edition in the database.
I had been invited to present on Edition Based Redefinition during yesterday’s launch event for Oracle 11gR2 in The Netherlands. Being the only non-Oracle staff speaker in the presence of (S)VPs was nice and my subject made it possible to tell one of the more interesting stories of the day – which was nice too. Below you will find the presentation I showed the audience yesterday. I will blog later on about the demo I showed – a simple SQL*Plus based demonstration of the multi-dimension world that EBR invites us into.
If you are interested to learn more –
and get some hands-on feel for this spectacular database facility – then join us next week (Tuesday 29th September) for the AMIS Query on Oracle Database 11gR2 (in Nieuwegein, in Dutch, free!). For details and to register, see: AMIS Query – 29 September 2009 – Introducing 11gR2.
Oracle 11gR2 On Line Documentation on Edition Based Redefinition.