Connecting to a Logical Server

Use the LogicalServer and NodeType connection parameters to establish the logical server context for a new user connection.

In a configuration file or at the Interactive SQL command line:

To specify the target logical server, add the LogicalServer=<target-logical-server> clause to a connect statement.
To specify the target logical server role, add the NodeType={READER|WRITER|ANY} clause to a connect statement.
For example, to connect an application that specifically needs to execute user-defined functions on member nodes with the READER role, use:
dbisql -c "uid=DBA;pwd=sql;eng=host4_iqdemo;LS=LogSvr1;NODETYPE=READER;

Note: When you connect using the SERVER logical server context, SAP Sybase IQ ignores the NodeType connection parameter.

Connections fail if:

The current node is not a member of any logical server assigned to the user's login policy.
The current login policy assigns SERVER logical server, and the user lacks sufficient system privilege.
The current login policy assigns NONE as logical server.
The current login policy assigns COORDINATOR as the logical server, and the user connects to a secondary server without enabling login redirection.

For new and upgraded databases, the default_logical_server login policy is AUTO. User-defined login policies use the value from the root login policy, which defaults to AUTO. When the default logical server policy is AUTO, login redirection never occurs, even if the LOGIN REDIRECTION logical server policy option. is set ON.

Under the AUTO setting, if the connection string fails to specify LogicalServer, SAP Sybase IQ automatically determines logical server context as follows:

Current Physical Node Status	Result
Node belongs to multiple logical servers assigned to a single login policy. A user belonging to that login policy logs in to the common node, but SAP Sybase IQ cannot determine which logical server to use.	Connection refused and error raised due to overlapping server scenario.
Node belongs to a single logical server.	Connection succeeds and context is that logical server.