November 6, 2003 at 2:30 am
Hello all;
I have 2 questions:
1. As far as I understood, doing a Full database backup is also backed up the transaction logs, however when displaying the database properties at the Enterprise manager I see the date only for the "Last database backup"
the "Last Transaction Logs backup" date is "None" (I do only Full backup). why is that?
2. Does the Full backup also caused to the transaction logs truncation or I need an explicit Backup Logs statement for that?
Thanks in advance;
November 6, 2003 at 4:10 am
Full backup only backs upenough of the tr log to do a restore.
You can restore tr logs across full backups - it is one of the reasons for doing them. If you have a corrupt full backup you can still go back to the the previous one nad restore all the log backups since. So obviously the full backup mustn't truncate the log.
If you are in full recovery mode and only doing full backups then the log will keep growing.
Cursors never.
DTS - only when needed and never to control.
Cursors never.
DTS - only when needed and never to control.
November 7, 2003 at 8:48 am
Correct me if i am wrong. To my understanding when u do a full backup the transaction log is also backedup and truncated. By doing full backup the log is also backed up within the database dump, there is no seperate file for log when a full backup is done. Only when u do an explicit log backup can u see the log file backed up date. U don't need to explicitely do a log backup, but if you want to recover the space used by the log u need to shrink the file .
November 11, 2003 at 2:17 am
Vambati, you are wrong. 😉
As Nigel said, full backups and log backups are independent.
If you do a full backup you get a backup of the database as it is. You do not need log backups to restore it. It does not backup of truncate the log.
If you use the simple recovery model the logfile is truncated on checkpoint and you neither can nor need to backup it.
If you use the full recovery model the logfile is only truncated on log backups. It will keep growing until you back it up. The log backup contains the information of all the changes in the database since the former logbackup (completely independent of the full backups).
The advantage of the full recovery model is that after you do a restore of a full backup you can restore log's till any log or time you like. In general people do a full backup once a day and several log backups during the day.
If I could do the following:
log backup 1
full backup 1
full backup 2
log backup 2
I can restore the present situation as follows:
restore full backup 2
restore log backup 2
But the following gets the same result:
restore full backup 1
restore log backup 2
That works because the full backup does not truncate the log.
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