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SQL Anywhere 12.0.0 » SQL Anywhere Server - Database Administration » Maintaining your database » SQL Anywhere read-only scale-out

 

Connecting to copy nodes

You can connect to a copy node by connecting to the primary server and specifying the NodeType connection parameter as part of the connection string. The NodeType connection parameter accepts the following values:

  • COPY   When the NodeType connection parameter is set to COPY, the database server examines the copy nodes in its own branch (including itself if it is not the root node) and chooses the copy node with the lightest load. If the database server does not choose itself, it redirects the client to the chosen database server.

  • DIRECT   This is the default setting. When the NodeType connection parameter is set to DIRECT, the database server accepts the connection without performing load balancing or redirection.

  • PRIMARY   If the NodeType connection parameter is set to PRIMARY and you have connected to the primary server, the connection is accepted. If you have connected to the mirror server or a copy node, the database server redirects the connection to the primary server.

Once the root database server determines which copy node should be used, the database server returns a connection string to the client containing the necessary information to connect to that node. The client then makes a connection to the copy node and communicates directly with its new parent database server for all further requests. The root database server determines which copy node to select as the parent based on status information that is sent to the root database server periodically by the copy nodes.

 See also