I have a table that has 1.7 million rows in and am trying to add a not null column. It runs for about half an hour and I get an error: ora 0115 IO error reading block from file (block # ). It does not display any block number or file number. Everything is online and all the data files are under 2G. any ideas on why I am getting this or how to resolve this? Oracle 8.0.5 AIX version 4.33.

Thanks
Sanjana