Oracle Backup and Recovery

You should be able to just do a restore/recover over top of the existing Host2. If you are trying to avoid a complete recovery, then I suspect the answer is you can't, but there are two notable exceptions.

1. If you never opened the database on Host2 and you have all the archive logs between the first backup and the second, then you can recover Host2 using them.

2. If you have opened Host2, you still might be able to do this if you have flashback database enabled and can flash back to the point before you opened it.

Each redo log file (and archived redo log file) contains starting SCN and ending SCN. In case it is a last redo, the ending SCN is 0xffffffffffff.

nap01:~/oradata/jt10g$ strings redo01.log|head -3
z{|}
JT10G
Thread 0001, Seq# 0000000004, SCN 0x0000000b05b5-0x0000000bd34f

nap01:~/oradata/jt10g$ strings redo02.log|head -3
z{|}
JT10G
Thread 0001, Seq# 0000000005, SCN 0x0000000bd34f-0x0000000bf612

nap01:~/oradata/jt10g$ strings redo03.log|head -3
z{|}
JT10G
Thread 0001, Seq# 0000000006, SCN 0x0000000bf612-0xffffffffffff

Until database sees 0xffffffffffff it keeps asking for further logs. But it is not a problem, you can specify UNTIL SCN or UNTIL CANCEL for your recovery (this means you don't want a complete recovery, in other words you want to lose some recent data).