Using Multiple Connection Types

A single instance of the database server can provide more than one type of connection. Figure 13 illustrates such a configuration. The database server is on host river. Client A connects to the database server with a shared-memory connection because shared memory is fast. Client B must use a network connection because the client and server are on different computers.

When you want the database server to accept more than one type of connection, you must take the following actions:

• Put DBSERVERNAME and DBSERVERALIASES entries in the ONCONFIG configuration file.
• Put an entry in the sqlhosts file or SQLHOSTS registry key for each database server/connection type pair.

For the configuration in Figure 13, the database server has two dbservernames: river_net and river_shm. The ONCONFIG configuration file includes the following entries:

DBSERVERNAME               river_net
DBSERVERALIASES            river_shm

Figure 13. A UNIX Configuration That Uses Multiple Connection Types

The dbservername used by a client application determines the type of connection that is used. In Figure 13 above, Client A uses the following statement to connect to the database server:

CONNECT TO '@river_shm'

In the sqlhosts file or SQLHOSTS registry key, the nettype associated with the name river_shm specifies a shared-memory connection, so this connection is a shared-memory connection.

Client B uses the following statement to connect to the database server:

CONNECT TO '@river_net'

In the sqlhosts file or registry, the nettype value associated with river_net specifies a network (TCP/IP) connection, so client B uses a network connection.