Yes I am personally sceptical that it will work, but you know mangement whishes! We are mainly using other datrabases than Oracle so I missed a bit new features.Therefore I thought, maybe ... just ask. Upgrades should mainly add new tables and columnd to existing tables. Antje -----Ursprüngliche Nachricht----- Von: Niall Litchfield [mailto:niall.litchfield@xxxxxxxxx] Gesendet: Dienstag, 13. November 2007 11:42 An: Antje.Stejskal@xxxxxxxxxxx Cc: oracle-l@xxxxxxxxxxxxx Betreff: Re: Update schema while new data is coming in I'd require of management and the customer that they only sent data to the old application that was entirely compatible with the new application. Or to put it another way it depends on the complexity of the application and the upgrade. If the new schema and application logic is 100% compatible with the old schema ( i.e you are just adding things on and not 'fixing' anything) then you'll likely get away with it - for a reasonable upgrade of a moderately complex application you are extremely likely to find data issues after the upgrade. On Nov 12, 2007 9:47 AM, < Antje.Stejskal@xxxxxxxxxxx <mailto:Antje.Stejskal@xxxxxxxxxxx> > wrote: Hi, we are having a web application that ist o be online availyble 7x24. We plan for the scenario that the application needs a software update (new tables , modified tables et. al.) Management and customer requires that the application is still running while the upgrade goes on. How would you solve this, that you have one server with the old schema where new data is coming in, meanwhile another server is brought up to latest release. And data of the old server (or delta of data) will be send to new server. We will propably have 2 servers anyway because of the traffic. Please help me with your ideas. Regards Antje Stejskal -- //www.freelists.org/webpage/oracle-l <//www.freelists.org/webpage/oracle-l> -- Niall Litchfield Oracle DBA http://www.orawin.info <http://www.orawin.info/>