Why is on-line backup one tablespace a time?

Dear all,

I read chapter 12 Overview of Backup and Reovery of Jason Couchman. An on-line backup is performed with one tablespace a time with: alter tablespace <ts> begin backup;
make backup of datafiles with OS copy command alter tablespace <ts> end backup;
These tablespace backups are not required to happen at the same time, and the database is still open. I wonder how these tablespace backups can be synchronized. Anyone comment on this? Thanks in advance.

Dino Received on Sun Aug 26 2001 - 10:03:18 CDT