Connection failover allows a client application to switch to an alternate
SAP Adaptive Server if the primary server becomes unavailable due to an unplanned event,
like power outage or a socket failure.
In a cluster environment, client applications can fail over numerous
times to multiple servers using dynamic failover addresses.
With high availability enabled, the client application does not need to be
configured to know the possible failover targets. SAP Adaptive Server keeps the client
updated with the best failover list based on cluster membership, logical cluster usage,
and load distribution. During failover, the client refers to the ordered failover list
while attempting to reconnect. If the driver successfully connects to a server, the
driver internally updates the list of host values based on the list returned. Otherwise,
the driver throws a connection failure exception.
Note: The connection
properties DEFAULT_QUERY_TIMEOUT and INTERNAL_QUERY_TIMEOUT or DriverManager.setLoginTimeout(xx) play vital role to switch over from
failed node to highly available node after failover occurs.