Table of Contents
Advertisement
The transaction log in backup, restore, and recovery
A second automatic checkpoint occurs at the end of backup. Any data that is
committed while the backup is in progress is included in any subsequent
backups. However, if a failure occurs between the first and second checkpoints,
any work that occurred after the first checkpoint cannot be restored.
Adaptive Server IQ backs up only those database blocks actually in use at the
time of backup. Free blocks are not backed up.
Adaptive Server IQ backs up the database files and the Catalog information
that pertains to the IQ database to which you are connected. It does not back up
the transaction log file. It does not use the transaction log to restore the
database.
If your database needs a rollback or is missing files, the backup fails.
Adaptive Server IQ uses the transaction log file during recovery from a system
failure. It does not use the transaction log to restore an IQ database, to recover
committed IQ transactions, or to restore the Catalog Store for an Adaptive
Server IQ database. However, the restore program does check for the existence
of the transaction log:
•
For a full restore, the transaction log must not exist. You must delete this
file before starting a full restore.
•
For an incremental restore, the transaction log must exist. You must not
delete this file or you will not be able to do an incremental restore.
Note
Adaptive Server Anywhere databases use the transaction log and other
logs differently. If you are recovering such a database, you need its transaction
log file, and
retains it for you. See the Adaptive Server Anywhere
BACKUP
User's Guide for details. Also, if you have data (other than the system tables)
in your Catalog store, transactions for that data can only be recovered if they
were written to disk before a failure.
CHAPTER 11
Backup and Data Recovery
379
Advertisement
Table of Contents
