Troubleshooting: How database servers are located

When SQL Anywhere locates a running server, it tries to locate or start the required database on that server. See Troubleshooting: How database servers are located.

If SQL Anywhere cannot locate a running server, it may attempt to start a personal server, depending on the connection parameters.

For local connections, locating a server is simple. For connections over a network, the Host connection parameter is recommended.
For information about how the client finds a network server see Troubleshooting: How the Host connection parameter locates database servers.
If the server is started automatically, then information from the START, DBF, DBKEY, DBS, DBN, Server, and AutoStop connection parameters is used to construct the options for the automatically started server. The server does not automatically start if the Host or the CommLinks=TCPIP connection parameters are specified.
If the server has an alternate server name, you can only use the alternate server name to connect to the database that specified the alternate server name. You cannot use the alternate server name to connect to any other databases running on that database server. See AS PRIMARY clause, CREATE MIRROR SERVER statement, and -sn database option.

The following diagrams illustrate how SQL Anywhere locates a database server.

When the connection string includes either CommLinks=ShMem, TCPIP or CommLinks=TCPIP, ShMem, then SQL Anywhere:

Attempts a shared memory connection, excluding attempts to autostart the database server. See Connection string does not include the CommLinks or the Host connection parameters.

If SQL Anywhere fails to locate the server using shared memory, then it attempts a TCPIP connection. See Connection string includes the Host connection parameter or the CommLinks connection parameter specifies TCPIP.