System recovery

In the event of a system failure or power outage, or when you restart the database server after it has been stopped, Sybase IQ attempts to recover automatically.

During Sybase IQ database recovery, any uncommitted transactions are rolled back, and any disk space used for old versions is returned to the pool of available space. At this point, the database contains only the most recently committed version of each permanent table.

During recovery from a system failure, Sybase IQ reopens all connections that were active at the time of the failure. If the -gm parameter, which sets the number of user connections, was in effect at the time of the failure, you need to restart the IQ server with at least as many connections as were actually in use when the failure occurred. Temporary table contents are not recoverable.

If a failure occurs, try to restart the database server and database. If you have trouble starting a server or database, or if users are unable to connect to it, see Chapter 13, “System Recovery and Database Repair.” You will need information from your server log and IQ message log to recover.

Sybase recommends that you run the stored procedure sp_iqcheckdb after a system failure, preferably before allowing users to connect. This procedure checks every block in your database, and produces statistics that allow you to check the consistency and integrity of your database. For details, see Chapter 13, “System Recovery and Database Repair.”