User's Manual

Chapter 11. Administering SQL Remote for Adaptive Server
Anywhere
Transaction log and backup management
The importance of good
backup practices
Replication depends on access to operations in the transaction log, and
access to old transaction logs is sometimes required. This section describes
how to set up backup procedures at the consolidated and remote databases to
ensure proper access to old transaction logs.
It is crucial to have good backup practices at SQL Remote consolidated
database sites. A lost transaction log could easily mean having to re-extract
remote users. At the consolidated database site, a transaction log mirror is
recommended.
☞ For information on transaction log mirrors and other backup procedure
information, see “Backup and Data Recovery” [ASA Database Administration
Guide, page 373].
Ensuring access to old
transactions
All transaction logs must be guaranteed available until they are no longer
needed by the replication system.
In many setups, users of remote databases may receive updates from the
office server every day or so. If some messages get lost or deleted, and have
to be resent by the message-tracking system, it is possible that changes made
several days ago will be required. If a remote user takes a vacation, and
messages have been lost in the meantime, changes weeks old may be
required. If the transaction log is backed up daily, the log with the changes
will no longer be running on the server.
Because the transaction log continually grows in size, space can become a
concern. You can use an event handler on transaction log size to rename the
log when it reaches a given size. Then you can use the
DELETE_OLD_LOGS option to clean up log files that are no longer needed.
☞ For more information about controlling transaction log size, see the
“BACKUP statement” [ASA SQL Reference, page 307].
Setting the transaction log directory
When the Message Agent needs to scan transaction logs other than the
current log, it looks through all the transaction log files kept in a designated
transaction log directory. A setting on the Message Agent command line
tells the Message Agent which directory this is.
Example For example, the following command line tells the Message Agent to look in
the directory e:\archive to find old transaction logs. The command must be
entered all on one line.
dbremote -c "eng=server_name;uid=DBA;pwd=SQL" e:\archive
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